The REI Flash 55 Backpack is an ultralight, roll-top backpack with an optional top lid pocket. Weighing 2 lbs 10 oz, it has a ventilated back to help keep your shirt dry in warm weather and numerous pockets and straps, called “packmods”, that can be removed or reconfigured to lighten it further, up to 7 oz. REI also added two additional side pockets to this year’s model, in addition to two side water bottle sleeves, in order to provide more external storage. Sizing can be a little tricky though, since this new REI Flash 55 is only available in a limited number of fixed length torso sizes, unlike last year’s model, which had an adjustable length frame. Make no mistake, the REI 55 is a true ultralight backpack and represents an exciting leap forward by the Co-op to make lighter weight backpacking more accessible and affordable. Plus, at $199, the price is right. A Women’s REI Flash 55 Backpack is also available.
Note: A new REI Flash 45 is also available. While slightly lighter weight (2 lbs 7 oz), it does not have a roll top.
Specs at a Glance
- Volume: 55L
- Gender: Unisex and Women’s available
- Frame: Internal, Perimeter Wire
- Ventilated: Yes
- Pockets: 10, including the main compartment
- Total weight: 2 lbs 10 oz
- Stripped Weight: 2 lbs 3 oz
- Torso Sizing: (S: 18 inches), (M: 19 inches), (L: 20 inches)
- Hip belt Sizing: (S: 30-40 inches), (M: 32-42 inches), (L: 34-46 inches)
- Maximum recommended load: 30 lbs
- Materials: 100-denier ripstop nylon main body; 420-denier nylon bottom; steel frame.
Backpack Storage and Organization
The REI Flash 55 is an ultralight-style roll top backpack with an optional top lid. The advantage of using a roll top is that it lets you compress loads from the top in addition to the sides using compression straps. This is useful if your load expands and shrinks during a trip, like when you resupply your food in town on a thru-hike or section hike. The nice thing about having an optional top lid is that you can add it when it’s needed, in cooler weather for example, to carry extra gloves, navigation gear, or smaller items that are handy to have easily accessible on longer hikes.
The Flash 55 top lid is also a floating lid, which is important because the pack has a long extension collar that extends above the top of the frame. Having a floating lid lets you raise its height, so it sits properly on top of your load. It also lets you wedge gear between the top of the main compartment and the bottom of the top lid, like a bear canister, tent, sleeping pad, etc, without having to put it into the main compartment. That greatly expands the pack’s utility on more remote or technical trips.
The main compartment of the Flash 55 is huge and it will hold a lot of gear and food. It has a hydration pocket inside with a central hang loop, but the rest of the space is unstructured and the only accessible is from the top. REI also, in what may be a first, recommends lining the inside of the Flash 55 with a “trash compactor bag as a waterproof liner for your main compartment.” Needless to say, a rain cover is not included with the pack.
The Flash 55 has a mesh front pocket that makes it easy to store damp or frequently accessed items, so you don’t have to stop and open up your pack to access them or put them away. The top of that pocket also hooks onto a plastic dongle for added security. One concern I do have it on the durability of the mesh used on the front pocket and the side water bottle sleeves, discussed below. While the mesh holes are small to prevent snagging, I question its durability for long-term use and off-trail. Solid fabric pockets or pockets made with stiffer, heavier duty mesh are much more durable.
The Flash 55 has two mesh water bottle sleeves (located directly behind the hip belt pockets but attached to the pack sides) to make it easy to reach the bottles while you’re wearing the pack. These were a feature on last year’s model and proved popular with users. The bottles sleeves are sized for tall skinny soda or bottled-water bottles and its easy to pull them out or replace them while wearing the pack. While you can also fit a 1 liter Nalgene in the mesh sleeve and pull it out, getting it back in is difficult because the bottle diameter is wider. Both bottles sizes also have a tendency to pop out of the sleeves when you put the pack down or its falls over. The sleeves have snap closures in front to hold the bottles in place, but they’re not totally effective, and they’re difficult to re-snap closed when wearing the pack.
REI has also added to solid paneled side pockets behind the water bottle sleeves for holding gear and longer objects, like tent poles, chair kits, fishing poles, etc and lashing them to the side of the pack with a compression strap. It’s an important enhancement, especially on a pack that will be used for longer distance trips. These pockets are not reachable when wearing the pack.
There are four additional pockets on the Flash 55, all of which are optional and can be removed. The floating top lid has an external top “Rainshield” pocket. That pocket is made with two layers of fabric and seam-taped, making it highly water-resistant. I hesitate to call it waterproof, because internal condensation is bound to make anything inside damp in prolonged rain. The top lid is attached by buckles and can be easily removed, as well as the straps holding it to the pack.
The hip belt pockets are also easily removable. One is mesh-faced and other has a solid fabric front. They’re large enough to hold an iPhone 6, a small point and shoot camera, or snack bars, but aren’t what I’d call big. They’re held on with a clever webbing strap/toggle system which holds them in place and prevents them from flopping as you bounce down the trail.
The Flash 55 also comes with a Rainshield shoulder strap pocket that’s attached to the shoulder pads using the same webbing/toggle system used by the pockets. It’s sized narrow for a Smartphone or a small camera. It snaps shut with a magnet, which always makes me leery on a backpack because it can interfere with a magnetic compass…but it’d be easy enough to cut out and replace with a velcro patch. It’s constructed like the top lid, with two layers of fabric and seam-taped, making it highly water-resistant. This pocket is a real value-add and saves you the expense of buying a similar accessory pocket.
Backpack Compression and External Attachment System
The stock REI Flash 55 comes with an elaborate but easy to use compression and external attachment system. You can use it out the box, as-is, remove the numerous straps (without having to cut them off), or move them around any way you need.
The four vertical corners of the pack have daisy chains loops running down them, implemented using cord, instead of traditional webbing. This is an increasingly common feature found on trail running backpacks, but it hasn’t really caught on yet with mainstream backpacks.
All of the straps and attachment points on the pack are girth hitched to the daisy chain instead of being sewn into the pack seams. This lets you detach them, move them to a different location, or change their angles, as needed.
REI even includes a mesh sack with the Flash 55 so you can store the straps you’ve removed between uses, and not lose them. Directions for attaching the straps are printed on the outside. Thoughtful.
All of the removable straps and pockets weigh 7 oz total. If you’re trying to reduce your pack weight, the biggest bang for the buck comes in removing the pockets (listed below), not the straps.
- the top lid w/ Rainshield pocket (1.9 oz)
- two hip belt pockets (1.6 oz)
- Rainshield shoulder strap pocket (0. 6 oz)
- two, two-piece upper side compression straps w/ buckle
- two, one piece lower side compression straps
- trekking pole/ice axe shaft holder
- two rear, short straps for top lid w/buckle
- two front, long straps for top lid w/buckle
The problem with removing the side compression straps is that you often can’t anticipate when you’ll need them to lash gear to the side of the pack. If you remove the top lid, you can get rid of up to four straps, though I’d still recommend keeping two of them to hold down the sides of the roll top. There are a lot of variations possible, though.
Backpack Frame and Suspension
The REI Flash 55 is a ventilated backpack with a suspended mesh panel to help keep you cooler and your shirt drier in warm weather. The mesh is stretched across soft dorsal and lumbar padding and integrated with the pre-curved wings of the hip belt. This provides a comfortable back-hugging fit, but won’t pull you backwards and off-balance, because the ventilation cavity is not as deep as that found on comparable packs, like the Osprey Exos.
The Flash 55’s frame is a lightweight, 360 degree steel perimeter wire (not removable). It provides great torsional flex, so it moves with you, as well as the horizontal rigidity that is important for proper load lifter function and hip belt load transfer. The hip belt is sewn directly to the pack, so that the load is carried very close to your core muscles and hip girdle for maximum efficiency, while the soft lumbar pad and pre-curved hip belt wings grip the iliac crest. I’m really quite impressed with the hip carry on the Flash 55, which is comfortable and does not slip down.
The hip belt closes with pull forward straps for mechanical advantage, with a single central buckle. The hip belt pockets are positioned a little farther back on the hip belt than I’d like, so I can’t see the zippers when I look down my sides, but whether they are for you will depend on your physical dimensions. I think the hip belt sizing for both the men’s medium and large sizes is optimistic in the upper half of the sizing range, but your mileage will vary. However, if the front of the hip belt doesn’t cover your hip bones, the pack isn’t going to fit you (See How Should a Backpack Hip Belt Fit?).
The shoulder straps have a unisex S-shape, with a rail-based sternum strap. They’re thickly padded and covered with a breathable mesh to wick away sweat. Both shoulder straps have elastic hose keepers as well as well a pair of short horizontal webbing straps to attach the Rainshield shoulder accessory pocket, which can be easily moved to the other shoulder strap. .
The sizing ranges for the men’s Flash 55 pack are quite narrow in terms of torso lengths and hip belt sizes (see specs above), so I’d encourage you to try on a few different sizes to zero in on a comfortable fit. Based on the numbers, I should be able to use a Flash 55 in a medium, but the large size fits better, both in the torso and the hips. If you’re between sizes, I’d definitely recommend sizing up.
|Make / Model||Price||Weight (oz)||Ventilated|
|REI Flash 55||$199||42||Yes|
|Granite Gear Crown 2 - 60L||$200||36.7||No|
|Hyperlite Mountain Gear SW 3400||$345||32.11||No|
|Osprey Exos 58||$220||43||Yes|
|Gregory Optic 58||$210||43.35||Yes|
|Zpacks Arc Blast 55||$325||21||Yes|
|Mountain Laurel Designs Exodus 57||$215||18||No|
|Mountainsmith Scream 55||$160||45||No|
|Sierra Designs Flex Capacitor||$200||41.2||No|
The REI Flash 55 is a highly configurable, ventilated, roll top backpack that weighs 2 lbs 10 oz, but can be stripped down to 2 lbs 3 oz by removing several optional components. If you’ve never owned a backpack that’s this lightweight, the Flash 55 is a good ultralight pack to cut your teeth on. Fully configured and out-of-the-box, with its top lid and full compression system, you can use it like your existing backpack as long as you don’t exceed its maximum recommended load of 30 lbs or gear, water, and food weight. If you want to experiment with removing the lid and just using the roll top, or in removing components, you can do that when you’re ready. Regardless, I think you’ll still be impressed at how well the Flash 55 carries compared to a heavier weight backpack with a more substantial frame.
If you’re a more experienced lightweight backpacker, switching to the Flash 55 can provide you with a lower cost way to reduce your pack weight than other comparable packs, with more features, and more flexibility. It’s also a far better backpack in my opinion than an Osprey Exos 58 (see our review) and better than the Gregory Optic 58 (see our review) if you prefer a roll top. That’s saying something, because these two packs are the industry leaders for sub 3 pound, ventilated backpacks at the $200 price point. My advice would be to try out the REI Flash 55 and compare them for yourself. This pack is a winner.
Disclosure: The author purchased this backpack.Editor's note: Help support this site by making your next gear purchase through one of the links above. Click a link, buy what you need, and the seller will contribute a portion of the purchase price to support SectionHiker's unsponsored gear reviews, articles, and hiking guides.
Most Popular Searches
- backpack with water bottle holder
- rei flash 55 review
- rei flash 55 reviews