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REI Flash 18 Review

Day Pack

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Best Buy Award
Price:   $40 List | Sale $39.95 at REI
Pros:  Affordable, minimalist design, lightweight, super packable
Cons:  Difficult access during activities, thin waist belt and shoulder straps
Editors' Rating:     
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Manufacturer:   REI


If you're looking for a lightweight pack that can accompany you on just about any mission you can dream up, AND you're on a budget, then look no further. For just under $40, the REI Flash 18 receives our Best Buy Award and is by far the lightest and most minimal product in our review.

This pack is a minimalist's dream, and scored the best of all the packs in weight and versatility. With a simple top-loading design opening into a single compartment, this pack remains comfortable during a myriad of activities.

The Flash 18 is an awesome lightweight pack that is less hiking specific pack than any we tested, but can most certainly transition between just about all of your activities, especially if you're on a budget and need a pack to take you from urban life to the mountain then to the crag. This pack climbs well due to its narrow profile, and is a great option for multi-pitch days and summit attempts.

If you want something more substantial but still lightweight, check out the Deuter Speed Lite 20.

New Version Available - May 2016
This award-winning daypack has been updated. Keep reading to find out more!

RELATED: Our complete review of day packs

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Analysis and Hands-on Test Findings

Review by:
Gentrye Houghton
Senior Review Editor

Last Updated:
May 21, 2015

The New Version of the REI Flash 18 vs. The Older Version

This pack has been updated as of 2016 and has a new look; we have contacted REI for additional details, though it is evident that the bag has an added daisy chain, with an ice axe loop. The pack is available in Titanium, pictured below, as well as Oregano, Black, and Vivid Viola (pink).

Check out the side-by-side comparison below, with the latest version pictured on the left and the older model shown on the right.
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Hands-On Review

As one of the most versatile packs we tested, and with a price you just can't refuse, the REI Flash 18 walks away with as our Best Buy award winner.

Performance Comparison

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Out on a light hike with the minimal and Best Buy winning REI Flash 18 through McClure Pass in western Colorado.


The greatest feature of the REI Flash 18 is its minimalism coupled with an amazing amount of versatility, plus, you really can't beat its price tag. It is hydration compatible and also comes with a single mesh internal pocket including a key clip for stowing smaller items. However, due to the placement of this pocket, it can be difficult to access if the pack is fully loaded. This may not be a problem, and even a plus if you're looking to safely carry items such as your cell phone, wallet, and keys, during long multi-pitch climbs.

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Out for a multi-pitch climbing day in Red Rock Canyon with the Flash 18, which climbed great.

The Flash comes with two daisy chains fixed to the outside for extra external carry options, such as clipping shoes. Another option is to attach a shock cord to the two daisy chains for quick stow-and-go items, like a jacket or other layers. There is also a loop for attaching your ice axe situated at the front base of the pack; however, the main drawback to this specific feature is that there is no upper attachment for the axe. You'll have to rely on your own MacGeyver engineering for this one.

Unfortunately, both the sternum strap and waist belt have pluses and minuses. The waist belt offers a little bit of stability, but the thin webbing becomes uncomfortable with heavier loads. The sternum strap does come equipped with a whistle; however, on larger torsos it does not lower enough on the shoulder straps for a proper fit, and can make you feel as though you're being choked. The good news is that both of these features are detachable.

Another drawback to this pack, especially if you are using it for climbing pursuits, is that the handle is part of the shoulder straps. It does not provide a good clipping point for attaching the pack to anchors or to use it as a haul bag.

This is the only top-loading pack with a drawstring closure system that we tested for this review; and while we love the narrow profile for ease of mobility, it does make reaching things at the bottom of the pack difficult without completely unpacking.

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The REI Flash 18 was the only top-loading pack we tested.


You can't beat the low weight and low price of this bag! Weighing in at just 12oz, it is the lightest pack we tested by far. It is a great little guy to have in your arsenal, even if you never use it for an actual day hike.


This pack sits comfortably on your back as long as you don't over stuff it. Due to the frameless back panel, it is easy to overload this pack, 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 10-15lbs. This is an essentials only type of pack! If you want a pack to carry more gear more comfortably, try our Editors' choice winner, the Osprey Talon 22.

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We wanted to know just how comfortable the Flash 18 was under heavy loads, so we weighted down with everything from 10 to 25 lbs.

One useful tip is that the light amount of padding in the back panel can be removed, and it provides a great cushion to sit on during your lunch break. If you happen to be looking for a little more structure in the back paneling, you can easily replace this foam with a stiffer version, or even a Sam Splint works great (and then you're doubly prepared!).


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 this pack and found that it worked well. It also works great for bike commuting or climbing and packs down to about the size of a softball so it can be brought on longer backpacking trips or travels as a separate daypack. In this scenario, it can be used as a stuff sack inside a larger pack, and then removed for use as a summit pack when needed.


Unfortunately, due to the drawstring closure on this pack, and even with the small flap designed to cover the opening, the Flash 18 was the least weather-ready pack we tested. During our 24-hour water test, the fabric seemed to shed water well; however, out of all the packs we tested, the Flash's contents were the most soaked at the end of the testing period.

We also lightly tested the ability for snow to work it's way in through the gap created with the drawstring. During our test, the pack remained snow free, but surely with more rigorous activity snow and ice would come through.

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Whether an avid hiker, or just playing around in the mountains, the Flash 18 is ready for anything.

This pack accompanied us while bushwhacking in Red Rocks National Conservation Area just outside of Las Vegas, Nevada. It not only came away unscathed from that adventure, but by the end of our testing period there were no apparent abrasions to the pack at all.

Ease of Use

Since this pack features a top-loading design similar to many backpacking packs, it is easy to load and held all of our 10 essentials during a pack test. There's not a whole lot of bells and whistles to this bag, which keeps it lightweight, but does sacrifice some comfort and organizational features. A 13-inch laptop will fit into this pack, however the pack itself does not provide much protection to any devices. While it is hydration compatible, a 3-liter bladder takes up a ton of space in the small bag, and once the bag is loaded, the inside smaller mesh pocket is hard to access.

Best Application

The options are pretty endless with this pack when you start balancing weight, price, and versatility. This pack is perfect for day hikes, grocery shopping, a school and gym bag, multi-pitch rock or ice climbing, and we love using it as a stuff sack inside larger packs and then using it during summit bids.


The Flash 18 is the least expensive of the packs reviewed, but also the least durable for rigorous backcountry conditions. We find it to provide the most value for the dollar. Not only is this pack super versatile and light weight, it is backed by the REI 100% satisfaction guarantee. Coming in at just under $40, the Flash 18 is our pick for the Best Buy award winner.

Other Versions

REI Flash 22 - Women's
  • Cost- $50

REI Flash 45
  • Cost- $129

REI Trail 25 - Women's
  • Cost- $69.50
  • This pack is women's specific

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See the side-by-side comparison, pictured left to right: REI Flash 22, REI Flash 45, REI Flash 62, REI Flash 58 - Women's, and REI Trail 25 - Women's.
  • The Flash series of packs by REI come in an assortment of sizes for all activities
  • Lightweight packs at their various sizes
  • Affordable price for quality back packs
  • Wide Variety of colors on many of the Flash series packs
Gentrye Houghton

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REI $39.95

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OutdoorGearLab Member Reviews

Most recent review: July 2, 2015
Summary of All Ratings

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100% of 1 reviewers recommend it
Rating Distribution
2 Total Ratings
5 star: 50%  (1)
4 star: 50%  (1)
3 star: 0%  (0)
2 star: 0%  (0)
1 star: 0%  (0)
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   Jul 2, 2015 - 04:04pm
MikeNYC · Hiker · New York
I have had mine for almost 10 years and it is the best 20 (on sale) dollars you can spend on a backpack. It is perfect short hike/summit pack. I found it to be surprisingly comfortable under 15 pounds and very durable. The materials are really lightweight, but because of the tall and slender design, it somehow resists abrasion. I have put a shock cords through the daisy chains, and in a pitch you can carry more outside of the backpack than fits inside. It is definitely a minimalist dream though you have to put some though into packing, since there is only one way to get to your gear. I have stratos 24 (which doesn't get enough love on this website) for more comfortable year-round use.
Last note, my 120mm BD z-poles fit perfectly inside of pack.

Bottom Line: Yes, I would recommend this product to a friend.
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