The REI Flash 18 is a sort of in-between bag that's light and packable enough you can bring it in your luggage but has a lot more features than ultralight options. As a small, top-loading bag without a weight-bearing hip belt, it's not meant for long day hikes with heavy loads but is a good option for shorter hikes around home, heading to the gym, or as a day bag on a longer backpacking trip. If 18 liters isn't enough for you, the Flash is also available in a 22-liter size.
REI Co-op Flash 18 Review
A good, grab-and-go bag for smaller users, but not ideal for long hikes or heavy loads.
Price: $40 List | $39.95 at REI
Pros: Lightweight, useful features, flap to cover cinch top, inexpensive
Cons: Small fit, hip belt not load-bearing
Manufacturer: REI Co-op
Cons: Small fit, hip belt not load-bearing
Manufacturer: REI Co-op
By Maggie Brandenburg ⋅ Senior Review Editor ⋅ May 14, 2019
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Our Verdict
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 This Product
REI Co-op Flash 18 | |||||
| Awards |  |  | |||
| Price | $39.95 at REI | $119.99 at Backcountry Compare at 2 sellers | $129.95 at Backcountry Compare at 3 sellers | $109.95 at Backcountry Compare at 3 sellers | $97.46 at Backcountry Compare at 2 sellers |
Overall Score  |
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| Star Rating | |||||
| Pros | Lightweight, useful features, flap to cover cinch top, inexpensive | Comfortable, lots of good features, water reservoir included | Comfortable, well-ventilated, adjustable torso length, included rain cover | Adjustable torso length, very durable, great features and pockets | Moves with you, durable build, well-balanced load carry, good pockets and carry options |
| Cons | Small fit, hip belt not load-bearing | On the heavy side, expensive | Heavy, ill-fitting hipbelt | Runs a bit small, front stow pocket a bit small | No hydration reservoir clip (loop only), not meant for downpours, very long torso |
| Bottom Line | A small, lightweight pack that'll work in a pinch. | An excellent option for extended day hikes and all sorts of activities. Hydration bladder included! | A great pack for those who hike in wet climates and who are on the smaller side. | A comfortable and durable pack that works as well around town as it does out on the trail. | Comfortable to carry even over long distances when fully loaded, with great balance and good features. |
| Rating Categories | REI Co-op Flash 18 | CamelBak Sequoia 22 | Osprey Sirrus 24 | Osprey Tempest 20 | Black Diamond Nitro 22L |
| Comfort (25%) | |||||
| Versatility (25%) | |||||
| Weight (25%) | |||||
| Ease Of Use (15%) | |||||
| Durability (10%) | |||||
| Specs | REI Co-op Flash 18 | CamelBak Sequoia 22 | Osprey Sirrus 24 | Osprey Tempest 20 | Black Diamond... |
| Weight (oz) | 9 | 36 | 41 | 26 | 31 |
| Volume/Capacity (liters) | 18 | 22 | 24 | 20 | 22 |
| Back Construction | Lightly padded back panel | Ventilated back panel with molded pods | Ventilated tensioned mesh | AirScape backpanel; large spaced padding covered by large-holed mesh | OpenAir backpanel; ridged foam covered by large mesh |
| Hydration | Internal hydration sleeve | External hydration sleeve and 3L Crux reservoir included | Internal hydration sleeve | External hydration sleeve | External hydration sleeve |
| Hipbelt | Yes, webbing and removable | Yes | Yes | Yes | Yes |
| Compartments | 1 | 2 | 1 | 1 | 1 |
| Rain Cover | No | No | Yes | No | No |
| Additional pockets | 1 | 7 | 5 | 8 | 5 |
| Outside Carry Options | Daisy chain, various small loops | Trekking pole and ice axe attachments, side pocket, hip belt pockets (one zip), daisy chain, hydration hose clip | Trekking pole attachment, ice axe loop, side strech pockets | Lidlock helmet attachment, trekking pole quick-stow, large stretch front pocket, ice tool loop with bungee tie-off, side pockets, hip belt pockets, sunglasses shoulder stow, bike light loop | Ice axe loops, dual 5-loop daisy chains, expandable side drink pockets, front stuff pocket, hip belt pocket, small zippered top pocket, four shoulder strap loops |
| Whistle | Yes | No | Yes | Yes | Yes |
| Key Clip | Yes | Yes | Yes | Yes | Yes |
| Materials | Ripstop nylon | 200D ripstop nylon, 400D plain-weave nylon | 210D nylon body, 420D nylon bottom | 70D x 100D nylon body, accent and bottom 420HD nylon packcloth | 210D ripstop nylon, 210D Dobby Abrasion |
| Notable Features | Internal storage pockets, removable back padding, cinch closure cover, removable sternum strap | Hydration bladder included, multiple pockets in both hip belts, internal storage pockets, exterior pocket felt-lined | Integrated rain cover, ice axe loop, trekking pole attachment, adjustable back | Helmet attachment, trekking pole quick-stow, sunglasses quick-stow, bike light loop, shoulder strap pocket, stowable ice axe loops | Bike light loop, main zip opens all the way down, ReActiv shoulder straps connect to each other behind the waist and waist belt not attached to frame to facilitate twisting, front expandable pocket reinforced with internal structural foam panels |
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Our Analysis and Test Results
The REI Co-op Flash 18 is the lightest, non-ultralight pack we tested, at just 9 ounces. It's made of ripstop nylon and features a top-loading cinch top design with a removable back pad.
Performance Comparison
Exploring an unexpected trail in Iceland with the REI Flash 18.
Comfort
The Flash has a thin, removable back panel that helps protect your back from the edges and hard surfaces of your gear a bit. While it's nothing like the super comfy padding of some of the fully-loaded models we tested, it's a marked improvement over the paper-thin construction of ultralight, packable models. It can also double as a sit pad when you want to take a break or have reached your destination. The shoulder straps aren't padded but do have some very light internal support as well as a design that takes the seam away from the insides of the straps, thereby alleviating some of those pressure points. The Flash also has a webbing hip belt for stabilization and a sternum strap, both of which can be removed.
Fold-over seams help keep pressure points away from your neck.
Versatility
The Flash has a good amount of pretty useful features that we think make this pack versatile beyond just a short day hike. A single exterior zippered pocket, several interior organizational pockets, and a key clip are handy for just about any adventure. This bag is also hydration compatible, with a dedicated pouch, loop, and hole at the top. There's also a daisy chain and ice axe loop for attaching gear that can't quite fit inside, as well as an emergency whistle on the sternum clip. Our favorite feature for this particular bag is the small flap that covers the hole at the top of this cinch-style bag. This flap helps deter water and debris from entering your bag and is something many other cinch-top bags lack.
A single daisy chain, ending in an ice axe loop don the back of the Flash.
Weight
Though it's not as impressive as the ultralight models, which each weigh less than 4 ounces, the Flash 18 isn't much more. This bag tips the scales at just 9 ounces, including all the removable straps and pads that you could leave behind to save weight. With no internal frame or extra padding to make it heavier, the Flash saves you some precious ounces. That being said, you're also sacrificing some comfort and durability compared to larger, beefier models. But we think these packs are best for different purposes anyway.
The Flash 18 is thin and light, but without cutting out every useful feature.
Ease of Use
As a top-loading pack, this bag can be tough to stay organized in or to dig out that last granola bar all the way at the bottom without completely upending the whole thing. And while we found the outer zippered pocket easy to get to while hiking, our main testers are also right-handed, and swing the pack around to the right side. Folks who tend in the opposite direction might not be so in love.
One feature we found incredibly easy to use is the cinch top itself. REI designed this with handy pull loops that mean you never have to pinch the plastic clip to open or close this bag. Much easier than the traditional cinch of other packs though. Though the Flash is sold as a "unisex" bag, we found it to be a fairly small fit, especially if you don't want to tighten it all the way up to the base of your neck. Taller or larger users may be happier with a larger option though.
We love the little flap that helps keep unwanted things out of the Flash.
Durability
REI doesn't disclose the thickness of the Flash 18's fabric, but to us, it feels somewhere around 70-100D of ripstop nylon. This seems incredible in comparison to the paper-thin feel of the several ultralight models we tested. But next to the beefy 210/420D of others, it's significantly less impressive. We also noticed that while the bottom panel is a bit thicker, it's also not ripstop. We didn't have any issues during our testing, but we wouldn't recommend dragging this pack across granite if you can help it.
The bottom of the Flash is thicker, but not ripstop.
Value
Retailing at one of the lowest prices of any model we tested, the Flash 18 is a pretty useful little bag. We think it brings pretty good value to the table for what it is. Though if you're on the hunt for a serious day hiking pack this probably won't cut it. But if this simple bag is what you need in your life, we think it's money well-spent.
Useful pockets, a key clip, and a place to stash a hydration reservoir make this a pretty versatile bag for a lot of different uses - how many can you dream up?
Conclusion
The REI Flash 18 threads the gap between big, feature-filled daypacks and tiny, packable ultralight packs. It cuts out framing and a lot of padding but keeps a host of useful features that come in handy for just about any adventure. If that in between stage sounds like what you want, then the Flash might be the perfect fit for you.
We enjoyed our short, lightweight jaunts in the REI Flash.
— Maggie Brandenburg