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Best Ultralight Backpack of 2021

We tested ultralight backpacks from Gossamer Gear, ULA, Osprey, and more to find the best pack for your needs
Photo: Tad McCrea
Thursday October 7, 2021
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Ready to join the ultralight revolution? Our thru-hiking experts purchased and tested over 25 products over the past seven years; for our 2021 update, we bring you the top 15 ultralight backpacks on the market. We've slogged along the John Muir Trail, hiked around Southern France's Haute Alpes, and traversed miles of talus in Argentine Patagonia to put these packs to the test. We've logged hundreds of trail miles to assess performance, subjecting each one to our rigorous testing metrics, including weight to volume ratio, carrying comfort, and features. Each year, the ultralight world grows and becomes increasingly competitive. This review highlights budget-friendly models and our top-ranked packs, as well as niche products.

Top 15 Product Ratings

Displaying 1 - 5 of 15
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Awards Editors' Choice Award  Top Pick Award Top Pick Award Top Pick Award 
Price $270 List$260 List$145 List$275 List$360.00 at Backcountry
Compare at 2 sellers
Overall Score
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77
Star Rating
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Pros Durable, comfortable, well-designed pockets, carries light and heavy loads wellLightweight, carries light and medium loads well, adaptable, perfect feature set, more durable than mostSimple design, inexpensive, durableCustomizable, great fit, comfortable, solid feature setDurable, simple design, lots of external attachment options
Cons Large capacity makes it less versatileA little small for a bear canisterFoam pad falls out easily, shoulder straps lack supportExpensive, lacks adaptability, lots of extra straps when compressedExpensive, lacks features, few external pockets
Bottom Line This pack wowed us with its perfect set of features, comfortable design, and carrying capacityDelivers a perfect set of features, plenty of pockets, comfortable straps, and carries wellA lightweight, simplified version of our favorite pack from this same company, making a durable, well-designed optionThis is a customizable, extremely comfortable, lightweight pack with a custom fitBuilt for serious adventures with lots of external attachment points and a durable construction
Rating Categories Gossamer Gear Mariposa Gossamer Gear Gorilla Adventure Equipment... Chicken Tramper 35... Hyperlite Mountain...
Weight To Volume Ratio (35%)
8.0
7.0
8.0
4.0
8.0
Comfort To Carry (25%)
10.0
10.0
6.0
9.0
7.0
Features (20%)
10.0
7.0
8.0
8.0
8.0
Adaptability (10%)
8.0
8.0
8.0
6.0
7.0
Durability (10%) Sort Icon
9.0
9.0
9.0
9.0
8.0
Specs Gossamer Gear Mariposa Gossamer Gear Gorilla Adventure Equipment... Chicken Tramper 35... Hyperlite Mountain...
Measured Weight 30.5 oz 31.5 oz 24 oz 29.8 oz 31.5 oz
Stripped Weight 30.5 oz 27.5 oz 23 oz 28.3 oz 31.5 oz
Claimed Volume 60 L 40 L 54 L 35 L 55 L
Measured Main Pack Volume 48 L 38 L 45 L 38 L 58 L
Measured Volume Total (minus hip belt and shoulder strap pockets) 64 L 53 L 53 L 38 L 58 L
Measured Volume Stripped (minus hip belt, shoulder pockets, and removable lids) 59 L 48 L 53 L 38 L 58 L
Average Weight-to-Volume Ratio (grams/Liter) 14 g/L 16.4 g/L 12.8 g/L 21.7 g/L 15.4 g/L
Carrying Comfort 15 pounds Great Great Great Good Great
Carrying Comfort 30 pounds Great Great Poor Great Good
Frame Type Foam pad/ removable stay Foam pad/removable stay Removable foam pad Removable carbon fiber Dyneema Hardline, removable aluminum stays, padded back panel
Fabric 70 & 100 denier Robic nylon 70 & 100 denier robic nylon 210 Robic nylon, 400d Robic Bottom Panel X-Pac VX21 210D Nylon Dyneema
Main Pack Pockets 4 3 3 3 None
Hip Belt Pockets 2 2 2 0 2
Single Hip Belt Pocket Capacity 4 4 cliff bars 2 cliff bars n/a 2 cliff bars
Shoulder Strap Pockets No No No No None
Whistle on Sternum Strap No Yes No Yes Yes
Internal Hydration Sleeve Yes Yes Yes No No
Bag Sizes/Torso Lengths Available S, M, L S, M, L S, M, L, XL S, M, L, or Custom sizing M, Tall, L
Mix and Match Hip Belt Sizes S, M, L S, M, L S, M, L, XL XS, S, M, L, XL No
Can Easily Strip Off Frame and Hip Belt Good Good No No No
BearVault BV500 Compatibility Good Ok Ok No Ok
Lid (aka Brain) No Yes No No No


Best Overall Ultralight Backpack


Gossamer Gear Mariposa


90
OVERALL
SCORE
  • Weight-to-Volume Ratio 8
  • Comfort to Carry 10
  • Features 10
  • Adaptability 8
  • Durability 9
Total Weight: 30.5 oz | Average Weight-to-Volume Ratio: 14 g/L
Comfortable with both light and heavy loads
Versatile
Great feature set
Well made
Fits bear canister
Heavier than some

Once again, against relentless competition from other brands, the Gossamer Gear Mariposa holds its place at the top of the fleet. This pack balances comfort with an emphasis on lightweight design in a way that is unparalleled. The feature set is thoughtful and useful but not overkill. It provides plenty of external-carry options without feeling weighed down by superfluous bells and whistles. The Mariposa had our favorite stretchy back mesh pocket, which was large enough to store extra layers, snacks, and other items we wanted to quickly access. It fits a bear canister and can carry a heavy load but can also be compressed to comfortably carry a smaller load. The fabrics used in its design are durable and lightweight; miles of bushwacking and talus-crossing hardly left a scratch.

Marketed as a 60-liter pack, the Mariposa can carry up to 64 liters when stuffed to the brim. For some, this may feel like too much room for an ultralight pack, as the more room you have, the more you may end up filling with unnecessary gear. It isn't the lightest in our review, though its 2.5-pound total weight and 14g/L weight-to-volume ratio are impressive. Plus, its slightly heavier weight added a level of comfort that was hard to beat.

Read review: Gossamer Gear Mariposa

Best Bang for the Buck


Osprey Exos 48


68
OVERALL
SCORE
  • Weight-to-Volume Ratio 4
  • Comfort to Carry 9
  • Features 8
  • Adaptability 7
  • Durability 8
Total Weight: 37.6 oz | Average Weight-to-Volume Ratio: 17 g/L
Good for medium loads
Inexpensive
Complete set of features
External storage and lashing options
Heavier than others
Not as durable as others

The Osprey Exos 48 combines durability and excellent features at an outstanding price. Its variety of pockets, straps, and attachment points allow for plenty of creativity if tinkering is your thing, yet its classic, user-friendly aesthetic works as-is for those who don't feel the need to modify. The Exos carries loads over 20 pounds with ease and excels when loaded down with over 30. The suspension system is one of the most developed of any pack in this review, and it provides a comfortable carry and impressive ventilation. Not only is it a pack with great value, but it is also an easy introduction to the world of ultralight equipment.

With a measured weight of two pounds 5.6 ounces, the Exos barely makes the cut as an ultralight pack. Our review has one of the higher weight-to-volume ratios, but it stands apart from most traditional backpacking packs. Its carrying capacity is relatively small (48 liters), which caters to those with an already trimmed-down kit. We were a little concerned with the long-term durability, as the stretchy side pockets quickly got holes, but we have no other concerns. The Exos is a tried and true favorite and has been around for a while; this means it is widely available online and in stores and is easy to pick up and take out on your next weekend adventure.

Read review: Osprey Exos 48

Best Weight-to-Volume Ratio


ZPacks Arc Blast 55


74
OVERALL
SCORE
  • Weight-to-Volume Ratio 10
  • Comfort to Carry 7
  • Features 5
  • Adaptability 5
  • Durability 6
Total Weight: 21.3 oz | Average Weight-to-Volume Ratio: 11 g/L
Extremely light
More or less waterproof
Lots of external storage options
Lightweight frame
No hip belt pockets (available add-on)
Complicated frame
Very specific

On the other end of the spectrum lies the ZPacks Arc Blast 55. It is a unique and highly specific pack in that it weighs almost nothing yet still can carry over 20 pounds. With a measured weight of 21.3 ounces, it's a great deal lighter than most in our fleet. Made from Dyneema Composite Fabric (DFC), it's incredibly durable, though the fabric is a bit stiff and crunchy. Beware of sharp metal edges (bear canisters or climbing gear), since they can easily be worn through the fabric. A relatively recent update includes changes to the straps, pockets, and waist belt. The pack has also seen a carrying capacity increase from 52 to 55 liters.

The Arc Blast is a slimmed-down ultralight machine with no bells or whistles. The frame is super light and a bit complicated; we do not recommend removing it unless you want to spend a great deal of time reassembling the pack. A bear canister only fits into this slender pack vertically, making it a little less-than-efficient to pack. We recommend this pack to any experienced ultralighter looking to strip a few ounces off their Big Four base weight.

Read review: ZPacks Arc Blast 55

Ideal for Small Capacity Adventures


Ultralight Adventure Equipment CDT


76
OVERALL
SCORE
  • Weight-to-Volume Ratio 8
  • Comfort to Carry 6
  • Features 8
  • Adaptability 8
  • Durability 9
Total Weight: 24 oz | Average Weight-to-Volume Ratio: 12.8 g/L
Simple feature set
Durable
Affordable
Full-sized, comfortable waist belt
Relatively small volume
Thin, unsupportive shoulder straps
Foam pad falls out easily

Ultralight Adventure Equipment consistently makes top-notch gear for the ultralight enthusiast, and the CDT is the latest addition to their fleet of durable, lightweight, hardworking packs. This pack is smaller than the previous model we've tested from ULA but still has many signature features that make these packs so well-loved. The CDT is meant for relatively light, small loads with a frameless design (a small foam panel for support in the back). That said, the waist belt is padded and soft, and the materials used in the pack's construction are rugged enough to handle the inevitable beat-down on the trail. Because of its size and design, it's ideal for loads under 20 pounds and can start to feel uncomfortable with 25+ pounds.

Though we loved the feature set of the CDT, it is relatively minimal. This pack is designed for folks who don't like extra frills — there are minimal pockets and external storage options. The cinch top closure also takes some getting used to (imagine a simple stuff sack) and does not completely protect from the elements. We loved this pack for short trips and light travel; it's also affordable, which adds to its allure.

Read review: Ultralight Adventure Equipment CDT

Best for Exceptional Durability


Hyperlite Mountain Gear 3400 Porter 55


77
OVERALL
SCORE
  • Weight-to-Volume Ratio 8
  • Comfort to Carry 7
  • Features 8
  • Adaptability 7
  • Durability 8
Total Weight: 31.5 oz | Average Weight-to-Volume Ratio: 15.4 g/L
Lightweight, yet very durable
Comfortable, considering its simplistic design
Low profile good for technical travel
Full-sized, comfortable waist belt
Expensive
Few external storage options

Missions in the mountains require packs that can handle two main things. First, the pack must be able to carry heavy loads. Second, it must be burly, which means it needs to offer protection from abrasions and keep its contents safe from rain and snow. The Hyperlite Mountain Gear 3400 Porter 55 does all of these things with style. It's simple and sleek, with a roll-top closure and lots of external lashing options. Its side straps can accommodate skis, boots, tent poles, or ropes, while its small waist belt pockets can hold snacks, phones, and sunscreen. We liked this pack's size, as it is a bit more versatile than some of its larger siblings from Hyperlite. The Dyneema used in its construction makes it one of the most durable and water-resistant packs we've tested.

Unfortunately, all of this comes at a cost. Hyperlite packs are some of the priciest on the market. You'll want to be sure this is the tool you need before throwing down so much cash. Also, if you're into pockets and features and bells and whistles, this pack may be a bit disappointing.

Read review: Hyperlite Mountain Gear 3400 Porter 55

An Excellent, Customizable Option


Chicken Tramper 35 Ultralight


68
OVERALL
SCORE
  • Weight-to-Volume Ratio 4
  • Comfort to Carry 9
  • Features 8
  • Adaptability 6
  • Durability 9
Total Weight: 29.8 oz | Average Weight-to-Volume Ratio: 21.7 g/L
Handmade to suit your exact torso dimensions
Extremely comfortable
Low profile design
Removable foam backpad
Expensive
Lacks adaptability

The Chicken Tramper 35 is well worth the wait. It took a little while to arrive at our testing facility because it was hand-made to fit our lead tester's dimensions. When it did arrive, we were immediately impressed by its overall design its apparent durability. This pack is burly! If treated kindly, it is the type of pack that will remain indestructible for years. We love the feature set, including the removable foam pad and the large mesh storage pocket. Its roll-top closure mechanism is simple and easy to use. The pack also comes with ice axe loops and shock cord on the sides for extra storage, making it an excellent mountaineering pack.

The downside to this pack is its price tag. It makes sense that a handmade pack with thoughtful features and incredibly durable materials would come at a cost. This could be a great choice for those who have been in the ultralight game for a while and want to upgrade.

Compare Products

select up to 5 products to compare
Score Product Price Our Take
90
$270
Editors' Choice Award
As an all around great pack, it can carry large and light loads with ease, has plenty of external storage options, and is super comfortable
81
$260
One of our top picks that scores highly in all metrics, it's comfortable, versatile, and has just enough features
77
$225
This pack is a popular ultralight pack for good reason; it has plenty of outside storage, is made of durable fabrics, and carries both 15 and 30 pound loads with ease
77
$360
Top Pick Award
Durable and simple; perfect for use in the mountains
76
$145
Top Pick Award
Combines simplicity, a reasonable price tag, and a good feature set
74
$325
Top Pick Award
As one of our highest scorers for ultralight enthusiasts, it's incredibly light, and still provides the same assets of a full frame pack
73
$140
Best Buy Award
Lacks a frame, pockets, and a lid, but fits the bill for an extremely lightweight, simple pack
73
$220
This 40 liter pack is designed for light and fast missions
72
$355
This pack is designed with a focus on durability and simplicity, with a minor emphasis on comfort and support
70
$160
This minimalist pack is lightweight and simple - designed for those who have slimmed down their kit to the bear minimum
68
$250
For a pack that is lightweight, but still provides support and ventilation with a full suspension system, this is the ticket
68
$255
This lightweight, comfortable pack has a simple, yet thoughtful design, and is a great pack for heavy loads or winter trips
68
$200
Best Buy Award
This high scoring pack has excellent comfort, durability, and a long list of useful features
68
$275
Top Pick Award
A lightweight pack that excels in its feature set and carrying comfort
67
$165
One of the lightest packs in this review, but also has a relatively small capacity

The Mariposa out for a few days hiking through the backcountry of...
The Mariposa out for a few days hiking through the backcountry of Grand Teton National Park. The pack has ample room in the side pockets for stoves, bottles, and food, while the mesh pocket is large enough for a few extra layers.
Photo: Jane Jackson

Why You Should Trust Us


Jane Jackson and Brandon Lampley spearheaded this review, bringing to the table a wealth of related experience. Two hundred+ days a year, you can find Jane outside using and testing gear. With years spent working and playing in the Yosemite backcountry, the Tetons, and the Wind River Range, as well as trips taken to the Alaska Range, the Himalaya, and Patagonia, Jane has spent plenty of time under the burden of a heavy pack. Brandon has hiked both the Pacific Crest Trail and Appalachian Trail, essentially back-to-back, with only four months off in between. He also has first ascents to his name in the Indian Himalaya and has summited Denali and Ama Dablam.

Our testing protocol consisted of both lab testing and trail miles. We independently test weight and volume measurements, as manufacturers have been known, at times, to fudge these numbers. We took it a step further and scored packs based on their weight per unit volume, which allows us to fairly compare models of different volumes. On-trail testing included trips such as 260 winter miles on the AT and 40 miles in the Black Rock Canyons Wilderness in Colorado. We also spent time in Patagonia and the Sierra High Country. Additionally, 15 and 30-pound test weights were used for shorter test laps for a more direct comparison.

Related: How We Tested Ultralight Backpacks

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Analysis and Test Results


In the past six years, we've tested over 25 models. For our 2021 update, we purchased the best 15 for hands-on testing. The products we've included represent the cutting edge in ultralight technology. If you're looking for larger frames and luxury padded waistbelts, you may want to look elsewhere; the packs in this review hardly resemble a traditional backpacking pack. There are many exciting small brands that have popped up in this category of outdoor gear over the past few years, and we've had fun assessing their latest products. Here, we evaluate the top products available for multi-month thru-hiking adventures as well as shorter alpine trips focused on fast and light backcountry travel.

Related: Buying Advice for Ultralight Backpacks

The Gossamer Gear Gorilla packed with equipment, food, and fuel for...
The Gossamer Gear Gorilla packed with equipment, food, and fuel for a five-day wintertime section of the Appalachian Trail. We covered a lot of miles to find the best ultralight backpacks. From the packing tests seen here, to the independent weight and volume measurements in our lab, we've done the most thorough side-by-side testing.
Photo: Brandon Lampley

Value


When making an outdoor gear purchase, we often trade off one thing for another, and no one understands trade-offs better than an ultralight enthusiast. We all spend too much time "weighing" our options. To bring a slightly thicker sleeping pad means foregoing powdered milk in the coffee…decisions, decisions. The weight savings that you can achieve often comes at the expense of something else. For example, the Granite Gear Virga 2 was one of the lightest options (10 g/L) but was also one of the least comfortable to carry a lot of gear with.

If you are looking for a good deal on a pack, but don't want to trade-off too much on the performance end, check out the Osprey Exos 48. The Exos provides ample support and weight a bit more than other packs in this fleet, so consider the Granite Gear Virga 2 for an incredibly light and inexpensive model. Another pack with a super simple design and a reasonable price tag is the Ultralight Adventure Equipment CDT, which costs just about the same as the Virga.


Weight-to-Volume Ratio


The weight-to-volume ratio is a measure we use here to compare packs and luggage of differing volumes. This heavily-weighted (no pun intended!) metric gets straight to the point; how much does this pack weigh relative to the volume it carries? Two sets of data, generated by our lab measurements, comprise this metric. First, we measured the weight of each model on our digital scale. Then, we weighed each pack with all modular components in place. Next, we examined each for a frame, waist belt, or other pockets that can be easily removed to pare the weight down for light loads. We then stripped these features off of each pack and weighed them again.


The most complex lab testing with these products is our independent measurement of pack volume; since nominal volume measurements from manufacturers are difficult to compare, we decided to perform our test. Although an ASTM standard exists for measuring pack volume and many pack manufacturers perform ASTM testing, some report the capacity of only the main pack as the nominal measurement, while others include pockets. The test doesn't provide for measuring external pocket volume, which is significant for these packs. In our experiments, we measured the volume of the main pack, the main exterior pockets, and the lid (when present).

After we filled the main compartment of each pack with ping pong...
After we filled the main compartment of each pack with ping pong balls to measure volume, we then measured the volume of external pockets and lids. We found all the top performing packs have similar total volume measurements.
Photo: Brandon Lampley

The weight-to-volume ratio is the most significant contributor to total scores, accounting for 35 percent. The Gossamer Gear Murmur, the Granite Gear Virga 2, and ZPacks Arc Blast 55 earned the best scores; these are three of the lightest packs we tested and forego many of the common features on other models. By combining an incredible weight-to-volume ratio with a surprising level of carrying comfort, the Arc Blast is excellent for ultralight enthusiasts.

The ULA Circuit and ULA CDT also earned decent scores for weight-to-volume ratio, and they each measured a tiny bit better than the middle of the field with all their modular components in use. Both were also top performers when we compared "stripped weight" to "stripped volume." We were especially impressed by the ULA Circuit, which has a larger carrying capacity than the CDT. Unlike the Granite Gear Virga 2 or the ZPacks Arc Blast, both of these are fully featured, with hip belt pockets, and can carry heavier loads in more comfort.

The Hyperlite Southwest provides durability, water resistance, and a...
The Hyperlite Southwest provides durability, water resistance, and a solid design.
Photo: Eric Bissell

Carrying Comfort


Of course, we all want an ultralight pack to be featherlight, but it must carry our load comfortably to be worth it. For each of these packs, we judged load-carrying comfort for two loads: 15 and 30 pounds. We then averaged each pack's performance in both categories to generate our carrying comfort score. Fifteen pounds is a perfect comparison weight for ultralight hikers on a short trip, while thirty pounds is a fair comparison weight for lightweight hikers on shorter trips, ultralight hikers carrying a week's worth of food, or for those brave enough to travel in the winter. While some packs can be stripped of their frame and waist belt, our evaluation of "great, good, or poor" for carrying 15 and 30 pounds is with the frame and waist belt in use, as these features add significantly to the comfort of carrying comfort a pack. We would only recommend stripping down a pack completely when carrying 12 pounds (or less) total weight.


The Gossamer Gear Mariposa, Gossamer Gear Gorilla, and the ULA Ohm 2.0 earned our highest scores in this category (for carrying both 15 and 30-pound loads). These three packs are the easiest to strip of their frame and waist belts if and when you want to take 12 pounds or less. At this low weight, we feel frames and even waist belts are not necessary.

Nearly every day out with these packs, we put them on the scale...
Nearly every day out with these packs, we put them on the scale before hiking, noting how well each carries 15 or 30 pounds (and the loads in between). At the end of our testing period, we also loaded each pack with 30 pounds, and hiked the same hill up and down to confirm our field testing.
Photo: Brandon Lampley

The Osprey Exos 48 is also important to mention in this metric. It carries 30 pounds more comfortably than any other we tested, but we found the tensioned frame a bit "turtle shell-like" when carrying lighter loads, meaning that the pack felt like it hovered awkwardly away from our back without weight (this affects its adaptability score more so than its comfort ranking). Similarly, but less noticeable is the Chicken Tramper. This pack carries heavy loads with ease and was one of the most comfortable packs we tested.

Like nearly all the Gossamer Gear packs, other slightly heavier models scored highly in the comfort metric due to their ample padding and suspension systems. These packs, in general, can carry both light loads and heavy loads comfortably.

To simplify our findings for load carrying comfort even further, we've broken down each of our three award winners' niches as far as load-carrying comfort goes:
  • Best for 10-20 lb loads: Best for Ultralight Enthusiasts: ZPacks Arc Blast 55
  • Best for 15-25 lb loads: Gossamer Gear Mariposa
  • Best for 20-35 lb loads: Osprey Exos 48
  • Best for 35+ lb loads: Chicken Tramper 35

Features


Manufacturers constantly seek to find the right balance of features for ultralight backpacks. Eliminating most creates a very light pack, but including the right features can significantly increase comfort, versatility, and ease of use. Some of the lighter full-sized packs we tested, like the ZPacks Arc Blast and Granite Gear Virga 2, earned top scores in our weight-to-volume ratio metric. However, this means that they are virtually glorified stuff-sacks with shoulder straps in terms of features (a.k.a. minimalist). By looking at their total scores, one can see trade-offs required to be the lightest of the bunch. This means reduced load-carrying comfort at heavier weights and reduced ease of use as a direct consequence of eliminating features.

Many of the newer packs we have added have a more balanced combination of weight, features, and comfort. Packs like the Gossamer Gear Murmur, the ULA CDT, and the Hyperlite Mountain Gear 3400 Southwest 55 all have a similar feature set, including a roll-top closure and three external shove-it pockets on the outside. Manufacturers seem to be trending in this direction, so consider that when looking at new packs, as lids are seemingly becoming a thing of the past.


The description of each pack's features you will find here has not been covered elsewhere at the same level. We've used these packs day in and day out, learning their quirks and fiddling with their features along the way. When covering big miles on the trail, features like easily accessible side pockets for your water bottles, waist belt pockets for snacks, and a convenient place to keep maps handy are a huge benefit. We also detail how each pack accommodates a hydration bladder and just how much stuff you can stow in the exterior pockets.

We love having easy access to snacks and layers with the Arc Blast.
We love having easy access to snacks and layers with the Arc Blast.
Photo: Eric Bissell

If you're crazy about features, check out the Osprey Exos 48, which incorporates so many features you'll never have to use the same pocket twice! While most manufacturers pick and choose which elements they think are the most useful, Osprey provides nearly every storage, lashing, and compression feature you can imagine. All these options are convenient but also contribute to the pack's relatively heavier weight.

The Gossamer Gear Mariposa also earned top scores in this category with its well-placed side pockets, over-the-top closure mechanism, and large mesh back pocket. The ULA Ohm 2.0 received high scores in this metric, though the Gossamer Gear packs both have a large external back pocket, which the OHM 2.0 lacks. We love how much you can stuff in the Gossamer Gear pack pockets compared to the small volume of the Ohm's exterior pocket.

Large external storage pockets are a classic feature common among...
Large external storage pockets are a classic feature common among ultralight packs.
Photo: Eric Bissell

Adaptability


While our carrying comfort metric focuses on how well each pack can carry a full load, our adaptability metric focuses on the pack's ability to scale its carrying capacity. While on a thru-hike or a week-long adventure in the backcountry, your total bulk and weight will fluctuate up and down. You'll encounter re-supplies and weekend trips where you'll sometimes need to carry a substantial load, but other times you may carry less. A pack whose design allows the frame and waist belt to be easily removed for very light loads is more adaptable.

While many of our testers have a quiver of packs suited for varying loads, a highly adaptable contender is critical when you seek one backpack to do it all. Packs can receive high scores in this metric when they have an easy-to-remove frame or simple design. These features allow it to carry minimal weight or to be easily packed with a massive load. The pack's overall design is versatile, too; we found it served its purpose as a lightweight model and was a fully functional pack for backpacking.


While stripping the pack down is an excellent feature for light loads, a kit that allows you to strap bulky but light items to the outside is a bonus when you need to carry big loads. These competitors have multiple ways to add things, like a closed-cell foam pad, to the outside. While, in general, we are not a big fan of lids for ultralight packs, they do create one key advantage: the ability to carry bulky items on top of the main compartment secured under the adjustable lid.

The Osprey Exos 48 and the Hyperlite Mountain Gear 3400 Southwest earned excellent adaptability scores because of their ability to carry heavy loads well with tons of external lashing options. The Hyperlite pack also has a very tall roll top, similar to the one on the ULA Circuit, which provides a great place to store extra bulky items when a significant food resupply occupies the main pack. The roll-top on the Chicken Tramper didn't compress as much as the Hyperlite packs, making it a bit less adaptable. The material used on the Chicken Tramper is stiffer and doesn't hold its rolled-up position very well.

Photo: Eric Bissell

Our adaptability score also considers ease of use with a bear canister. This will be irrelevant to some, but bear canisters are required by regulation on some portions of the PCT and AT. The BearVault BV500 is perhaps the most common bear canister used by weight-conscious hikers in areas where bearproof food storage is required in the backcountry. We loaded each pack up with a standard three-season kit and five days of food in the BV500 to see how well it fits inside and how much room is left over for the rest of your stuff. If you regularly carry a bear canister of this size, the Gossamer Gear Mariposa is compatible with this can.

The very tall top of the Windrider 3400&#039;s main pack allows you to...
The very tall top of the Windrider 3400's main pack allows you to scale up and down in pack volume. When you go big, you will want your lightest bulky items up top.
Photo: Brandon Lampley

Durability


How durable can a sub-two-pound backpack be? The answer is that most are surprisingly durable. That said, many of these packs require a little more care and attention than load monsters that weigh five or six pounds and use much heavier fabrics and frames. If you plan to carry more than 30 pounds most of the time, the packs in our backpacking review may serve you better. So how durable should an ultralight backpack be? As a baseline, to achieve an above-average score, we estimated that a pack must last for a least one thru-hike of a trail like the PCT or Appalachian Trail. The best of these packs will see you through many thousands of trail miles!


Many factors go into our rating for durability, which contributes 10% of the total scores. First and foremost, we consider the types of fabric used for the pack's main body and the exterior pockets. These areas are subject to abrasion, especially the pockets (if you tend to stuff a lot into them). There are always trade-offs in design. A pack that is made of incredibly light fabric will probably be less durable than one made from robust 200D nylon ripstop.

The main fabric of the ULA Circuit is likely the most durable over the long haul, but its carbon frame is a liability for rough handling. Our durability rating also considers frame durability and pocket fabrics.

Additionally, the stretchy exterior pocket fabrics that we love for function tend to be more prone to snagging on tree limbs or abrading on rock (compared to non-stretchy pockets). Unfortunately, it seems that you can't have it all. In our experience, a stretchy main exterior pocket with durable side pockets is the best compromise. This type of design is found on the award-winning Gossamer Gear Mariposa. When it comes to materials, the Gossamer Gear Murmur is made of some of the most delicate we've seen in this review, and that should be considered when thinking about this product.

While it is the case that you'll need to treat your pack with care (it is your home on your back!), we also take into consideration whether sitting on it while it is loaded or rough handling in the back of your van or truck could damage the frame. To this end, we think that if you are focused on durability or if you know you're rough on your gear, you'll want to think about choosing a pack with an aluminum frame versus carbon fiber. The rugged aluminum frame is one of the many small factors that lead us to prefer both of the Gossamer Gear packs to the two ULA packs. The carbon rod frame found in the ULA Ohm 2.0 and the ULA Circuit is significantly more fragile. Out of our top scorers, the Mariposa is one model we felt comfortable sitting on without the worry of breaking something.

Durability should be taken into account when comparing the price...
Durability should be taken into account when comparing the price, weight, and construction of a pack.
Photo: Eric Bissell

Key Accessories


A rain cover for your backpack has long been one of the key accessories to ensure your ultralight backpacking kit stays dry through rainstorms. The Gregory Octal's UL Raincover is a reliable and widely available choice, as are the covers from Sea to Summit. That said, if you plan to travel in places with notoriously bad weather, like Patagonia, for example, it may not be a bad idea to consider investing in a Hyperlite pack, which in our experience provided unparalleled protection from the elements, even on the wettest days.

Each of these packs comes with its own unique feature set; it&#039;s up...
Each of these packs comes with its own unique feature set; it's up to you to decide what features are important to you.
Photo: Eric Bissell

Waterproof roll-top style dry bags or Cuben stuff sacks are an excellent choice for both organization and moisture protection inside your backpack. Sea to Summit's ultralight Sil-Nylon bag is also an ideal choice. For those seeking to shave off the grams, Hyperlite Mountain Gear, ZPacks, and several other ultralight manufacturers produce a large variety of Cuben fiber storage and stuff sacks.

Lining your backpack with a contractor's plastic garbage bag, or better yet, a trash compactor bag has long been a great option to ensure your kit stays dry during long rainy days on the trail. While one of these should last you for a week or more with a little care, you would replace it often while thru-hiking. Cuben fiber pack liners are the state-of-the-art in super light and durable waterproof pack liners. The models available from ZPacks are the best we've seen.

An ultralight backpack is just one of the many products featured in our Dream Backpacking Gear List. Check it out for all of our "dream" backpacking gear and clothing in one spot!

If you're interested in cutting weight even further, you can use a sleeping pad as a back pad in a frameless backpack.


Conclusion


We hope the information in this review sparks an interest in the ultralight world. If all the gear required feels overwhelming, simply getting a lightweight pack is a wonderful place to start. A light pack automatically jumpstarts the transition toward lightening up the rest of your kit. The packs in this review range from extremely slimmed down to more comfy options for those unwilling to part with the standard backcountry creature comforts. Our testers have worn loads of different packs outside of the ultralight world as well and have a breadth of experience that will help guide you toward the pack that is right for you.

We hiked high and low, from the Continental Divide to the...
We hiked high and low, from the Continental Divide to the Appalachian Trail, to find the best ultralight backpacks! Here, Brandon celebrates another beautiful day in Rocky Mountain National Park with the Osprey Exos 48.
Photo: Brandon Lampley

Jane Jackson & Brandon Lampley