REASONS TO BUY
Affordable
Minimalist design
Lightweight
Super packable
REASONS TO AVOID
Few extra features
Thin shoulder straps and hip belt
REI Co-op Flash 18 Review
A simple pack that's easy on the wallet, ultralight, and super popular
Credit: REI Co-op
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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. See our review on the best daypacks to find out how the Flash 18 fared next to its competitors in our testing lineup.
Our Analysis and Test Results
Check out the REI Flash 18 for one of the most versatile daypacks 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
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.
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.
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.
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.
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.
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.
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.
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.
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Jacob Clark
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