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REI Co-op Flash 55 Review

The REI Flash 55 may not be heavy load hauler, but for moderate loads, this pack is comfortable and has an amazing set of features
Best Buy Award
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Price:  $199 List | $199.00 at REI
Pros:  Light-weight, comfortable, easily personalized, inexpensive
Cons:  lacks durabillity, not made for heavy loads
Manufacturer:   REI
By Adam Paashaus ⋅ Review Editor  ⋅  Apr 21, 2020
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#3 of 18
  • Suspension and Comfort - 45% 7
  • Weight - 20% 10
  • Features and Ease of Use - 20% 9
  • Adjustability - 15% 5

Our Verdict

The Best Buy for this season is given to the REI Flash 55. The Flash is a comfortable pack that carries a medium load well but is not intended for loads much over 30lbs. Even with a ton of pockets and features, the pack is super light-weight due to thin fabrics and a lighter duty suspension. The hip pockets, top lid, shoulder strap pocket are all removable to save an additional 7oz, and the side compression straps can be (re)moved to better suit the pack's load, regardless of the trip. For those wanting a light-weight pack with a lot of versatility will love this option, and with its low price, we think this is a perfect pack for those looking to keep a trimmed-down pack load.

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Our Analysis and Test Results

.The REI Flash 55 is a cleverly designed pack, giving the user a way to personalize the feature set. We think this pack is a great option for a wide range of users. For being such a light-weight pack, we were surprised by how comfortably it carries the load.

Performance Comparison

The Flash 55 is a great fast and light pack  for all types of adventure.
The Flash 55 is a great fast and light pack, for all types of adventure.

Suspension and Comfort

The Flash 55 is a light-weight pack that isn't made for large, heavy loads but has a max recommended load of 30 pounds. Instead of having a hard plastic frame sheet and aluminum stays, it uses a spring steel perimeter style frame for a suspension that feels as though it moves with you, yet supports the max load weight, and does so quite comfortably.

The 3D contoured back panel and waist belt have carefully positioned padding to keep the pack comfortable and supportive, yet allow air to escape through the gaps, keeping the wearer cool, and the padding is the perfect density to offer good support and cushioning.

The well-spaced foam padding on the waist belt and back panel is the perfect density to comfortably support the weight.
The well-spaced foam padding on the waist belt and back panel is the perfect density to comfortably support the weight.

The shoulder straps, which are intended to support less of the load than the waist, have a slightly less-dense cushioning with breathable mesh up against the body to help move the air. We found the pack hugged the body well and we never had any complaints about the way it felt, even on the longest days on trail.

Features and Ease of Use

REI is likely proud of the Flash 55 and its Packmod(ular) design. It has a handful of really clever features that can be removed, or adapted to help make packing for any trip a breeze. The modular aspects include two hip belt pockets (one mesh, one ripstop), a waterproof shoulder strap pocket (seemingly made specifically for a phone), compression straps, top lid, and tool attachment loops.

We especially love the Rain Shield shoulder strap pocket. With a seam-taped construction and a magnetic flap closure, it was the perfect place for a phone so it can be on-the-ready and in a waterproof (albeit not submersible) location. This pocket can be removed completely or switched from the right shoulder strap to the left.

The Hip pockets are also pretty great. Both pockets are large enough to hold a phone (if it's not already in the rain-shield shoulder strap pocket of course) or plenty of snacks, a map and compass, headlamp, or any other small items you may want to have on-the-go. These pockets can also be removed from the waistbelt altogether. One of the pockets uses a stretchy mesh, and the other is made with ripstop nylon.

The side compression straps, also part of the Packmod system, can easily be repositioned up or down the side of the pack to get the optimal positioning to secure any load, or I suppose, if you don't' want them at all, they could be removed.

The Packmod compression straps can be moved up and down or angled differently to make sure that you can effectively stabilize the load.
The Packmod compression straps can be moved up and down or angled differently to make sure that you can effectively stabilize the load.

The top lid is another Packmod feature that can be removed if you don't need or want it. The lid is fully seam-taped and ready to keep your items dry unless the bottom really drops out. While this is a simple feature, it adds peace of mind that the contents inside will remain dry even if you get caught in a quick shower. The main pack body is closed with a roll-top dry-bag style closure to help compress the load to the right size, keeping the contents stable even if you choose to leave the top lid at home.

Everyone loves a good breathable, stretchy mesh front stash pocket, and the Flash 55 doesn't disappoint. In fact, they go a step further by offering two more cavernous external pockets (non-stretchy), one on each side, between the side bottle pockets and the front mesh pocket. We found them super handy for layers, lunch, water filter, etc. The less we have to open the main compartment on a hike the better, and these extra pockets allow for nearly unlimited packing options. This pack is hydration compatible, but no pack is complete without a set of side bottle pockets, and these may be the best-executed bottle pockets we've ever come across. They hold wide-mouth bottles with ease, and with the help of a strap that can be snapped partially across the opening, it even does a great job of holding narrow mouth bottles without them flopping around. To keep bottles easy to grab, many pack makers let you load the bottles in sideways. However, most bottles put in this way will get in the way of your natural arm swing. The Flash 55 keeps the bottle in the vertical orientation, but because they are positioned so far forward, they are easy to grab for even those who may not have the most flexibility.

The Flash uses one main pack body, rather than incorporating a separate sleeping bag compartment. For our testers, that was preferred, but others may enjoy that as a feature. There are no handy straps positioned on, either the front of the pack or underneath for stowing a closed-cell sleeping pad, but you could easily strap one under the top-lid if desired.

With all the Packmod items and their extreme versatility, we think the Flash 55 is by far one of the most feature-packed bags in our tests.


We loved how light REI made the Flash. With the weight being so low, you wouldn't think this pack would carry a lot. However, when loaded up to its max 30lbs, this pack still carries extremely comfortably, even on long days when the sun gets low, and camp can't come soon enough. At 2lb 10oz (2lb 3oz without Packmod items) the Flash is a featherweight, and assuming it doesn't get overpacked, it is a great load hauler.

Adjustability and Fit

With no way to adjust the torso length, this pack has to be purchased in a specific size. However, each size has enough adjustability to make sure that you get a good fit even if you are on the border between two sizes.

The waist belt padding is fixed in place as well. While the webbing on a medium will allow for up to a 42" waist, the padding will only reach around so far, making the pack less comfortable for those on the larger end of the size range. Overall, assuming you get the right size, the fit on this pack for most people is excellent!

Testing in Southern Utah.
Testing in Southern Utah.


We awarded the Flash 55 our Best Buy for good reason. For those looking for a light-weight pack that is comfortable and user friendly, this pack is a great option definitely worth a look. At the price, we think this pack has a lot to offer.

It should come as no surprise that with thinner fabrics and lighter weight designs, that durability will be sacrificed. We did find a few small holes in the pack sides after only a few days on the trail from the pack rubbing up on rocks.


The Flash is an incredibly light, extra comfy, feature-packed, versatile, low priced, well-designed pack, made for those looking to keep things streamlined and light-weight. If you are wanting a serious load hauler, this is not the best choice, but if you keep the weight down to around 30 pounds at the most, this is a killer pack at a great price.

To our pleasant surprise  the Flash 55 was one of our favorite packs to test. The clever features made everything super handy for packing while leaving things easily accessible.
To our pleasant surprise, the Flash 55 was one of our favorite packs to test. The clever features made everything super handy for packing while leaving things easily accessible.

Adam Paashaus