Expanded Features Analysis of REI Co-op Flash 55 Backpack

Fabric: The main body of the pack is built with 100 denier recycled nylon Robic ripstop. It’s lightweight, durable, and now sustainable. Robic was the former gold, but now silver standard for lightweight backpacks (since bested by the likes of Dyneema and Challenge Ultra).

Main Compartment: The ~40L main compartment of REI Co-op Flash 55 will store the bulk of your gear, and is sized to accommodate modern lightweight equipment and sensible packing, for which there is plenty of room. That being said, it may feel a bit small if you have a piecemeal gear set comprised of inexpensive hand-me-downs, old bulky gear, mixed with luxury car camping items. This is a common challenge for beginner backpackers to run into; you don’t know what you don’t need, so you just bring too much of everything.

The Flash 55 is reasonably large, but small enough to force you to make good decisions and pack the right gear. We encourage you to choose Flash 55 over some gigantic, heavyweight 70L pack. Bigger is not better most of the time! This pack volume size is a perfect growth opportunity for beginners to become intermediates.

Back Panel: The aerated foam back panel is lightweight, comfy and reasonably breathable. This one gets good marks from us and is the exact same as what’s found on the more expensive Flash Air 50. No back panel can prevent sweat, all they can do is reduce it slightly.

Frame: The spring steel piping frame is in the shape of two squares stacked on top of each other, and does a good job of transferring weight from the shoulders to the hips. You probably won’t notice it much, but it does its job well and that’s what counts.

Shoulder Straps: The shoulder straps are thick and comfy. But a couple of minor downsides include the lack of a daisy chain loops for attachable custom pockets, and the use of a sternum strap slider beam instead of a nylon webbing adjuster or daisy chain increments. Speaking generally (not specifically to this pack) sternum sliders are prone to falling off the beam, or moving around over the course of a day.

Front Pocket: We’re reasonably happy with the front pocket because it is fairly large. That being said, we also have some bones to pick with how they’ve designed it. First off, the way it buckles closed instead of cinching is less desirable and adds steps to access/re-seal. And while this pocket is large, we wish it had more slack or some degree of stretch. When the main compartment is completely full, it expands from inside, reducing the usable volume of that pocket. The mesh panels on the sides are good for breathability and drainage, but we view them as likely to tear and become damaged as they can snag and tear on sharp rocks or other natural hazards.

Side Pockets: The Flash packs have a unique side pocket configuration. The most interesting part is that there are two medium sized pockets per side, rather than one large pocket as can be found on most packs. The smaller of the two pockets is placed into the gap between the hip belt and normal side pocket position, using a space that would have otherwise gone to waste, so that’s smart. What’s more, these pockets are oriented forward so people with moderate-to-good shoulder mobility can reach back to access with out taking the pack off. If you have low shoulder mobility, you will still struggle to use these pockets. It may also feel weird as the bottle may contact your hips a bit as you walk. These pockets are sized for a 1L Nalgene bottle, and narrow Smartwaters will jiggle about.

The taller, more traditional side pocket, sized for a Smartwater-shaped bottle, are very tall, and kind of slim. We wish they were a bit shallower, and a bit girthier. And the lower of the two side compression straps is situated inside this pocket, which can create additional friction/stick-points as you put stuff in or pull it out. All said and done, Flash packs have a unique take on pockets, but we aren’t convinced it’s better than the traditional one-large-protruding-side-pocket system used on most ultralight packs.

Hip Belt and Hip Belt Pockets: The pre-curved aerated foam hip belt is comfy and nice, and the best part about it is that you probably won’t notice it much because it does its job well. The reverse pull buckles are easy to use and adjust on the go. The removable-ness of the hip belt pockets seem a bit silly. These are the most-accessed pockets on the pack; in the backcountry you will be using them constantly every day, so there’s basically no reason to ever remove them. It just adds manufacturing cost and failure points. While the hip belt pockets are sufficiently sized, we ding them slightly for not having lower gusseting to add volume (the bottom of the pocket is basically 2-dimensional/flat), while the top is wide and 3D. As such, they performer smaller than they look.  What’s more, there is absolutely no reason that the right pocket should be made of mesh, it’s just not durable enough for that location and is definitely a small-but-notable downside.

PackMod Accessories: Unfortunately, we’re not fans of REI’s PackMod pockets. The shoulder strap pocket is too small, and its mesh body is not durable enough. The hanging mesh pocket bounces around as you walk and should be removed entirely.

Lid Compartment: The lid compartment is great for storing small accessories and snacks, and can also be worn as a waistbelt. Most experienced backpackers choose ultralight backpacks without lid compartments, instead favoring a Y-strap. But either way, it’s nice to have extra storage on top.