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REI Co-op Flash 18 Review

A simple pack that's easy on the wallet, ultralight, and super popular
REI Co-op Flash 18
Credit: REI Co-op
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Price:  $40 List | $39.95 at REI
Pros:  Affordable, minimalist design, lightweight, super packable
Cons:  Few extra features, thin shoulder straps and hip belt
Manufacturer:   REI
By Jacob Clark ⋅ Review Editor  ⋅  May 25, 2022
Our Editors independently research, test, and rate the best products. We only make money if you purchase a product through our links, and we never accept free products from manufacturers. Learn more
67
OVERALL
SCORE


RANKED
#10 of 14
  • Comfort - 25% 5.0
  • Weight - 25% 10.0
  • Versatility - 25% 6.0
  • Ease of Use - 15% 7.0
  • Durability - 10% 4.0

Our Verdict

We've owned a Flash 18 since this backpack debuted in the late 2000s. We've used it in most environments under most weather conditions, ranging from day hikes to long, multi-pitch climbs and everything in between. Its low price, super low weight, and superb simplicity mean that we'll likely own a version of this pack for a very long time. It is a minimalist's dream and scored highly in weight and versatility. With a simple top-loading design opening into a single compartment, this pack remains comfortable during a myriad of activities. This is an especially good choice if you're on a budget and need a pack to take you from urban life to the mountain and then to the crag. This pack climbs well due to its narrow profile and is an excellent option for multi-pitch days and summit attempts.

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REI Co-op Flash 18
This Product
REI Co-op Flash 18
Awards  Editors' Choice Award Best Buy Award Top Pick Award  
Price $40 List
$39.95 at REI
$139 List
$139.00 at REI
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$70.00 at Amazon
Compare at 2 sellers
$80 List
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Overall Score Sort Icon
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Pros Affordable, minimalist design, lightweight, super packableComfortable and stable, intuitive and functional design, modular set-up, utilizes recycled materialsLightweight, only includes essential features, comfortable suspension for the weightSimple, lightweight, versatileSimple, durable, versatile, inexpensive
Cons Few extra features, thin shoulder straps and hip beltNon-adjustable frame, large size for minimalist outingsUncomfortable with heavy loads, lacks durabilityA little small, lacks high-end featuresNo padded waist belt, heavy for the volume and features
Bottom Line A simple pack that's easy on the wallet, ultralight, and super popularTop comfort and stability make this pack the right fit for hauling your gear on any outdoor excursionThis pack is an excellent value, providing all-around performance for light and fast activities at a bargain priceA simple and lightweight hiking backpack that serves a dual purpose with a laptop sleeveA simple, durable backpack for the casual to enthusiastic day hiker that is also suitable for commuting and multi-sport use
Rating Categories REI Co-op Flash 18 REI Co-op Traverse 32 REI Co-op Flash 22 Osprey Daylite Plus REI Co-op Trail 25
Comfort (25%)
5.0
10.0
6.0
7.0
5.0
Weight (25%)
10.0
8.0
9.0
7.0
7.0
Versatility (25%)
6.0
7.0
7.0
6.0
7.0
Ease of Use (15%)
7.0
8.0
8.0
8.0
8.0
Durability (10%)
4.0
9.0
5.0
6.0
8.0
Specs REI Co-op Flash 18 REI Co-op Traverse 32 REI Co-op Flash 22 Osprey Daylite Plus REI Co-op Trail 25
Volume 18 L 32 L 22 L 20 L 25 L
Measured Weight 9.5 oz 41.0 oz 14.0 oz 20.6 oz 30.9 oz
Back Construction Simple foam pad Contured, foam pad Removable foam pad Mesh over vented foam Contured, foam pad
Hydration Compatibility Internal hydration sleeve Internal hydration sleeve, hook and loop attachment point Internal hydration sleeve Internally accessed sleeve, holds up to 3L, bladder not included Internal hydration sleeve
Hip Belt 3/4" webbing, removable 1 3/8" webbing, countoured padding, ventilated outer layer Broad, not padded. 3/4" webbing, removable 3/4" webbing
Number of pockets 2 7 5 6 6
Description of Pockets 1 cinched main compartment, 1 outer zippered 1 main combo top-loader/side panel zip, 1 internal mesh w/ overlap closure (inside of lid), 1 external zip on top of lid, 2 mesh side bottle w/ button closure/expansion, 2 oversized hipbelt zip 1 main compartment, 2 mesh side bottle pouches, 1 side zippered pocket, 1 top pouch 2 stretchy mesh side, 1 interior padded laptop sleeve, 1 back zippered with internal mesh dividers and key clip, 1 back expandable waterbottle, 1 back zippered. 3 stretchy mesh side, 1 top zippered, 1 main compartment zippered, 1 bottom zippered for rain cover
Materials Nylon Nylon Nylon Nylon
Outside Carry Options 1 exterior daisy chain, ice-axe loop Trekking pole lash points, ice axe attachments, daisy chains,attachment loops, compression straps Tool loop and bungee holder Side compression strap Daisy chain, ice axe, pole loops, sleeping pad straps (bottom and top)
Whistle Yes Yes Yes Yes Yes
Key Clip No Yes Yes Yes Yes
Other Notable Features Removeable foam back panel doubles as sit pad, removeable sternum and hip belt straps Steel frame w/ 1 internal stay, hydration tube holder on shoulder strap, included rain cover, water bottle pockets angled forward to allow on the go access Removeable foam back panel doubles as sit pad, removeable sternum, removeable Packmod bungee Compatible as an attachment to other Osprey packs None

Our Analysis and Test Results

Check out the REI Flash 18 for one of the most versatile backpacks we've tested, at a price you can't refuse. It carries light loads securely, is easy to stuff and dump out quickly, and can easily find its way on all but the most gear-intensive adventures.

Performance Comparison


REI Co-op Flash 18 daypack - ready for trips to a coffee shop or up to a peak, this minimalist...
Ready for trips to a coffee shop or up to a peak, this minimalist pack packs a punch.
Credit: Jacob Clark

Comfort


This pack sits comfortably on your back as long as you don't overstuff it. Due to the frameless back panel, it is easy to overload, causing the back paneling to round. The shoulder straps are thin and breathable but are the first source of discomfort when weighing this pack down with anything over 10-15 pounds. Unlike the very similar Flash 22, the shoulder straps are not padded, which turns out to make a big difference in comfort. This is an essentials-only type of pack. If you want a pack to carry more gear more comfortably, look for packs with a more robust suspension.

Quick and simple is the goal of this pack, including the easy...
Quick and simple is the goal of this pack, including the easy adjustments of the sternum strap and shoulder strap.
The clean and simple hip belt is quick to adjust and easy to remove.
The clean and simple hip belt is quick to adjust and easy to remove.

The Flash 18 is a one-size-fits-most pack, but we found that across a range of torso sizes, from a 5-foot, 5-inch tester to a 6-foot, 5-inch tester, we could cinch the suspension tight on the shoulders for bouncy trail running, or let some out and get the weight at least partly on the hips for hiking. When cinched down, it didn't bounce and hugged the torso well, making it ideal for long runs. For further reduced bounce, there are small daisy chain loops on the sides of the pack, with a bit of string and simple knots the pack can be fashioned into makeshift compression straps. Careful though, like overpacking, too tight on the compression, and the back panel may start to round.

Weight


The low weight and low price of this bag are a great combination. Weighing in at only nine ounces, it has a super low weight to volume ratio of 0.51 ounces per liter. Other packs provide more features, but few can compare to the low weight of the Flash 18.

REI Co-op Flash 18 daypack - the flash 18 has a simple frameless design with a single foam back...
The Flash 18 has a simple frameless design with a single foam back panel insert and removable hip belt.
Credit: Jacob Clark

Versatility


Due to the lightweight, minimalist design, this pack has versatility beyond a typical daypack. One of our testers ran the Grand Canyon from rim-to-rim and back with a version of this pack and found that it worked well. The Flash 18 also works great for bike commuting or climbing and packs down to about the size of a softball. The packability of this pack lends to travel and a summit bag when backpacking at minimal weight. If you don't plan on using it this way, then perhaps you should consider if this feature is worth the loss of comfort and ease of use.

REI Co-op Flash 18 daypack - despite its simple and minimal design, rei kept a few simple...
Despite its simple and minimal design, REI kept a few simple features including the whistle buckle on the sternum strap and hose routing for hydration bladders.
Credit: Jacob Clark

Ease of Use


The Flash 18 is a relatively simple pack but has what you need for many different adventures. It is hydration compatible and also comes with an external pocket including a key clip for stowing smaller items. It has a daisy chain fixed to the outside for extra external carry options, such as clipping your shoes on. There are eight total perimeter daisy chain loops next to the back panel that you can clip things to, or use to secure cordage for extra lashing options. At the base of the pack, there is also an ice axe loop making a nice simple addition to a potential summit pack.

REI Co-op Flash 18 daypack - the simple top-loading compartment is easy to access on the go.
The simple top-loading compartment is easy to access on the go.
Credit: Jacob Clark

The waist belt is a simple thin piece of webbing that adds some extra stability but not much comfort and the sternum strap comes with a whistle. Both of these features are detachable. Unlike past versions of this pack, this model has a nylon carry loop at the top and an added side access zippered pocket.

A simple side pocket with internal organization adds functionality...
A simple side pocket with internal organization adds functionality at little cost to weight.
Tiny cord loops helpful for strapping gear to the pack or even...
Tiny cord loops helpful for strapping gear to the pack or even weaving a line through for an added compression system.

While the pack can accommodate a laptop and a 3-liter hydration bladder, there is little protection and the bladder takes up most of the room in the pack.

Durability


During our testing period, the Flash 18 performed surprisingly well. A simple cinch flap covering the top of the pack helps keep water out, however as it is only a flap, it didn't do so for long. The coating on the rest of the pack did well to repel water, though the pack did show signs of seeping through, at the seams, and through the fabric if there was some pooling present. In light rain or intermittent rain, this pack will keep most of the contents dry, but for extended weather, a liner or a pack cover might be needed. A simple trash can liner inside would work quite well with the simple design of the pack.

REI Co-op Flash 18 daypack - an extremely packable pack ready to tuck into a larger pack as a...
An extremely packable pack ready to tuck into a larger pack as a summit bag or take travelling abroad.
Credit: Jacob Clark

Through months of testing, including bushwhacking through dense foliage in Red Rocks National Conservation Area, the pack survived without noticeable wear. On a side note, however, one tester hauled an older version of this model up 90 feet on the Diamond of Long's Peak. It scraped its way up, snagging along the way, and eventually arrived at the belay battered and torn, but was still usable. For what it's worth, that version and the newest version seem to be made of the same material. The Flash packs are also remarkably easy to repair, having very simple construction. Just clean it up, slap on some tape, and it's good to go.

Value


The Flash 18 is one of the least expensive of the packs we've reviewed, but also the least durable for rigorous backcountry conditions. We find that it provides an excellent value for the dollar given its versatility and super lightweight.

REI Co-op Flash 18 daypack - dreaming of the next adventures this pack will surely go on. perhaps...
Dreaming of the next adventures this pack will surely go on. Perhaps the mountains or a distant country. Either or, it can do both.
Credit: Jacob Clark

Conclusion


For the weight and price, this specialized and compact pack deserves your attention. The super-simple design is ultralight and very inexpensive, a hard-to-find pairing. Other packs are more durable and supportive of heavy loads, but for smaller missions and for tucking into the corner of your bigger bag, the Flash 18 gets the job done.

Jacob Clark
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