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. Still not enough capacity for your liking? The Cotopaxi Luzon 24L is a similar bag that's a bit larger and with features, we found rather conducive to the variety of travel.
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
RELATED: The Best Women's Daypacks of 2019
Our Verdict
Compare to Similar Products
 This Product
REI Co-op Flash 18 | |||||
| Awards |  | ||||
| Price | $39.95 at REI | $150 List Check Price at Amazon | $129.95 at Backcountry Compare at 3 sellers | $110.00 at Amazon | $148.20 at Amazon Compare at 3 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 | Compact, adjustable, comfortable for a light bag. | Large capacity, good back ventilation, adjustable torso, included rain cover |
| Cons | Small fit, hip belt not load-bearing | On the heavy side, expensive | Heavy, ill-fitting hipbelt | No rain cover, hip belt pockets are made of mesh. | Runs small, heavy, expensive, large for average day hike needs |
| Bottom Line | A good, grab-and-go bag for smaller users, but not ideal for long hikes or heavy loads. | A versatile daypack that can hold a lot of gear. | This pack is loaded with features, and if it fits, you'll love it! | A light and simple daypack that is perfect for quick jaunts on the trail. | The biggest and most comfortable daypack in our test group. Great for heavy loads and big days out. |
| Rating Categories | REI Co-op Flash 18 | CamelBak Sequoia 22 | Osprey Sirrus 24 | Lowe Alpine Aeon ND20 | Gregory Jade 28L |
| Comfort (25%) | |||||
| Versatility (25%) | |||||
| Weight (25%) | |||||
| Ease Of Use (15%) | |||||
| Durability (10%) | |||||
| Specs | REI Co-op Flash 18 | CamelBak Sequoia 22 | Osprey Sirrus 24 | Lowe Alpine Aeon... | Gregory Jade 28L |
| Weight (oz) | 9 | 36 | 41 | 29 | 42 |
| Volume/Capacity (liters) | 18 | 22 | 24 | 20 | 28 |
| Back Construction | Lightly padded back panel | Ventilated back panel with molded pods | Ventilated tensioned mesh | Air Contour backing with Flexion harness | Crossflow suspension |
| Hydration | Internal hydration sleeve | External hydration sleeve and 3L Crux reservoir included | Internal hydration sleeve | External hydration sleeve | Internal hydration sleeve |
| Hipbelt | Yes, webbing and removable | Yes | Yes | Yes | Yes |
| Compartments | 1 | 2 | 1 | 1 | 1 |
| Rain Cover | No | No | Yes | No | Yes |
| Additional pockets | 1 | 7 | 5 | 5 | 6 |
| 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 | Trekking pole and ice axe attachements, side pockets, helmet attachment | External stretch pocket, trekking pole holders, ice axe attachement, sunglasses loop and bungee, hip belt pockets, hydration hose clip |
| 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 | Abrasion-resistant nylon coated with TriSheild | 210D nylon body, 420D nylon bottom |
| 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 | Ice axe loop, trekking pole attachment, adjustable back | Ice axe loops, trekking pole attachment, adjustable back | Adjustable torso length, internal pocket, cinch straps, sunglasses quick-stow |
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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 the CamelBack Sequoia 22, our Editor's Choice award winner, it's a marked improvement over the paper-thin construction of ultralight models like the Osprey Ultralight Stuff Pack and Sea to Summit Ultra-Sil. 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 the other cinch-top bag, the Cotopaxi Luzon lacks.
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 the Cotopaxi Luzon. 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, like the Luzon.
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 40D Stuff Pack and 30D Ultra-Sil. But next to the 210/420D of the Osprey Sirrus and Gregory packs we tested, it's 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.
Best Applications
We think the Flash 18 is a good quick-grab bag for short hikes, running errands, or to stuff into a backpack or suitcase for a small excursion later. If you're looking for a pack you can load down with supplies for you and the kids and the dog and head out for the day, we'd recommend something with more padding and structure (and capacity!), like the Gregory Jade 28.
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?
Value
For the low price of just $40, 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 without a serious price tag, we'd recommend a pack with a hip belt but a similar low price, the Gonex 35L. If your errands around town involve heavy, bulky items, you might instead consider the Osprey Tempest 20, our Top Pick for Around Town. But if this simple bag is what you need in your life, we think it's $40 well-spent.
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. Though if you're a taller or larger pack-lover, you might consider a larger, but similar bag, the Cotopaxi Luzon 24L instead.
We enjoyed our short, lightweight jaunts in the REI Flash.
— Maggie Brandenburg