How to Choose a Backpack
REI Co-op Flash Air 50 Pack - Men's
$299.00
Members get an est. $29.90 in rewards
Inspired by thru-hikers across North America, the men's REI Co-op Flash Air 50 pack is our lightest backpacking pack yet—perfect for those who like to stretch the miles without sacrificing comfort.
This purchase pays for membership!
$29
10% Reward
on this and every eligible full-price item*
+
$30
Bonus Card
valid for 60 days after joining*
=
$59
Value
Start earning when you buy a $30 lifetime membership.
Keep shopping
- Ultra-high-molecular-weight polyethylene (UHMWPE) fabric is amazingly durable and allows for a surprisingly long lifespan for such a lightweight pack
- Nonfluorinated durable water repellent (DWR) helps moisture bead up on the surface
- 3D contoured hipbelt and ventilated back panel are comfortable all day for loads up to 25 lbs.
- Roll-top lid provides weather resistance and allows compression and adjustment of internal volume
- For a tight load and good balance, Packmod compression straps (included) can be run from any loop to any other loop, so you can sculpt your pack to the shape of your load
- Packmod mesh pocket on the shoulder strap is great for phone, snacks, sunglasses and more—or you can take it off altogether to reduce weight
- Compatible with Packmod hipbelt lengthener and Rainshield pocket (accessories not included)
- Water bottle pockets are positioned forward on the hipbelt so you don't have to remove the pack to grab your drink; cinch closures keep a good grip on slim water bottles
- Exterior side pockets and hipbelt pockets are great for storing light items that you want to keep handy
- Large front pocket is great for rain shell or other gear you may need to access quickly
- Top Y-strap helps you store excess items, including some bear canisters, on exterior of pack
- Attachment loops and removable tool keeper allow trekking poles, ice axes and more to be lashed on, expanding your carrying ability while keeping the load stable
- Daisy chain with multiple attachment points allows for tailoring exterior loads
- Internal hanging loop secures a hydration reservoir (not included); pack design allows tube to be routed over either shoulder
- Also comes with a handy mesh pouch (6.3 x 8.7 in.) to store or organize removed Packmod accessory straps or other small items
- Contains materials that meet the bluesign® criteria
- REI Co-op brand is certified to The Climate Label; we actively fund efforts to reduce carbon emissions across our business and support climate projects around the world
Imported.
View the REI Co-op Flash Product LineView all REI Co-op Backpacking Packs| Best Use | Backpacking |
|---|---|
| Frame Type | Internal Frame |
| Ultralight | Yes |
| Gear Capacity (L) | S: 49 liters M: 50 liters L: 51 liters |
| Gear Capacity (cu. in.) | S: 2,990 cubic inches M: 3,051 cubic inches L: 3,112 cubic inches |
| Weight | S: 1 lb. 13 oz. M: 1 lb. 14 oz. L: 1 lb. 15 oz. |
| Fits Torso Length (in.) | S: 18 inches M: 19 inches L: 20 inches |
| Fits Waist/Hips | S: 32-40 inches M: 34-42 inches L: 36-46 inches |
| Material(s) | UHMWPE ripstop nylon (87% nylon/13% polyethylene; bluesign approved) |
| Frame Material | Spring steel |
| Reservoir Compatible | Yes |
| Pack Access | Top |
| Number of Exterior Pockets | 8 + main compartment |
| Raincover Included | No |
| Hipbelt Pockets | Yes |
| Dimensions | S: 26 x 14 x 12 inches M: 27 x 14 x 12 inches L: 28 x 14 x 12 inches |
| Gender | Men's |
| Sustainability | Contains materials that meet the bluesign® criteria From a Climate Label Certified brand |
Buying Advice
Better gear is built together
From feedback to field testing, all of our gear is dialed-in by REI Co-op members. Their adventures informed every stitch and detail—making for better, longer-lasting gear.
Review this Product
Adding a review will require a valid email for verification
Most Helpful Favorable Review
Flash Air 50% More (Did NOT receive free product.)
REI Member1 year ago
Hi. If you'd like to hear from someone not incentivized to give glowing feedback in exchange for more free stuff, here's a review from someone who did NOT receive a free product. I tried and inspected this pack in-store. Quick advice? Skip this and get the Flash 55—or something else—instead. At 50% more costly than the Flash 55, you essentially get the same pack as the Flash 55, yet without the brain and other goodies you get with, and have the option to remove from, the 55. If you remove all the packmods and brain from the 55, you can achieve a weight very close to that of the Air 50. I think the 5 cubic liters difference between the two packs is in the optional brain included with the 55, so the main body capacity is likely the same. Note also that the hip-belt pockets are NOT removable on the new Air 50, whereas they are on the 55. Ugh. Regarding price, REI caught the greedflation bug and overpriced this pack. It should cost the same or less than the Flash 55. Would you pay more for a base-model car than for the same model car with more features? SUMMARY: REI missed an opportunity to make this pack unique. Instead it stripped down its Flash 55 and raised the price 50%. Skip the Air 50 or wait till its price is lowered. REI should be bringing us quality gear at lower costs since there's no middleman between it and us. Instead of using resources to make products no one buys and get marked down 70% (ahem, Outdoor Afro clothes, REI-branded shoes), REI, please focus on making bread-and-butter camping gear, like packs and tents, better and cheaper for your devoted members. We’ll thank you.
REI Member
176 people found this review helpful
Most Helpful Critical Review
Flash Air 50% More (Did NOT receive free product.)
REI Member1 year ago
Hi. If you'd like to hear from someone not incentivized to give glowing feedback in exchange for more free stuff, here's a review from someone who did NOT receive a free product. I tried and inspected this pack in-store. Quick advice? Skip this and get the Flash 55—or something else—instead. At 50% more costly than the Flash 55, you essentially get the same pack as the Flash 55, yet without the brain and other goodies you get with, and have the option to remove from, the 55. If you remove all the packmods and brain from the 55, you can achieve a weight very close to that of the Air 50. I think the 5 cubic liters difference between the two packs is in the optional brain included with the 55, so the main body capacity is likely the same. Note also that the hip-belt pockets are NOT removable on the new Air 50, whereas they are on the 55. Ugh. Regarding price, REI caught the greedflation bug and overpriced this pack. It should cost the same or less than the Flash 55. Would you pay more for a base-model car than for the same model car with more features? SUMMARY: REI missed an opportunity to make this pack unique. Instead it stripped down its Flash 55 and raised the price 50%. Skip the Air 50 or wait till its price is lowered. REI should be bringing us quality gear at lower costs since there's no middleman between it and us. Instead of using resources to make products no one buys and get marked down 70% (ahem, Outdoor Afro clothes, REI-branded shoes), REI, please focus on making bread-and-butter camping gear, like packs and tents, better and cheaper for your devoted members. We’ll thank you.
REI Member
176 people found this review helpful
Customer Images
underpickled
Received free product
Oakland, CA
Very light, versatile, and comfortable
2 years ago
The Flash Air 50 pack is a very light, but spacious backpack ideal for through-hiking or backpacking. It has a lightweight frame and a few extra pockets other than the main compartment, but that's really all I feel is necessary. Just enough to be useful, but not so much that it adds too much weight or limits flexibility by forcing a particular packing style. Plus it was comfortable to wear. I never loaded it up super heavily, but that isn't really what this pack is for. A few things I liked in particular: - The hipbelt felt like just the right size and amount of padding. With other backpacks I've struggled with being able to tighten the hip belt enough before each side runs into the other, but this flt spot on (for reference, I'm 5'7", a size 30 waist for jeans, and usually wear size "small" of most brands). - The pockets in the hip belt were actually spacious enough to fit a few bars comfortably and were easy to access, another area I've had issues with from other packs. - The elastic cord around the rear mesh pocket was a nice touch, adding some retention for the layers you might want to stash there as the temperature changes - A mesh bag that hangs on one side (and a smaller one on the front left strap) allows you to pack something wet and give it a change to dry out. Both are removable if you want to shave some grams. - Rolltop. Love a rolltop bag! In addition to the standard rolltop clip closure, there is another elastic-cord clip that holds the rolled portion in place, which is a nice touch. My main gripe was that my bladder of choice (3L/100oz Osprey Hydraulics Reservoir) did not fit at all in the bladder sleeve. This was disappointing and a bit surprising, since it fits all of my other packs, including a much smaller one. That being said, I'd be shocked if this didn't fit other bladders, maybe even the updated version of mine, since I have an older design (which you can see in the picture). Not a deal breaker for me since a pair of Nalgenes will easily fit in the side pockets, but I felt I had to dock a star for that. Overall I'm quite happy with this pack. There are a number of small, thoughtful design decisions that I really appreciate, and it's a great size for the type of lightweight backpacking its suited for. I wish it would fit my bladder, but maybe that problem is specific to me.
Age:25–34
Yes , I recommend this product
RSP1
Received free product
Seattle, WA
Great Ultralight Backpack!
2 years ago
This pack qualifies as an “Ultralight” weighing in at 30.6oz (based on my scale, not an official weight published by REI). When considering a lightweight pack, you should be aware of the trade-offs. To save weight, ultralight packs typically use thinner materials, don't have a separate top storage compartment, and use draw strings instead of heavier zippers. The hip and shoulder straps are also usually less padded and often the packs aren’t adjustable to suit different torso lengths (so choose your size wisely!). With the above caveats, I’m impressed with the Flash Air 50 and give it a 5-star rating. Strengths: - Very lightweight and comfortable. Hip and shoulder straps are nicely padded for an ultralight pack. - The main outside pocket holds everything I would typically place in the top compartment of a pack. Tightening the draw string keeps everything in place and secure. - Two nice sized pockets on the hip belt and a super convenient mobile phone pocket on the left shoulder strap. - The two pockets on either side of the hip belts securely hold water bottles. The water bottles are easy to reach without the need to take off your pack. Areas for Improvement: - On the inside of the pack, there is a sleeve for a water bladder. There are two stiff wires running along the inside of the sleeve (presumably for structural support). The wires prevented me from easily inserting a water bladder. - The pack comes with a removable water bottle holder that you could hang off the back of your pack or from one of the shoulder straps, however, I quickly removed it after realizing a swinging 2lb water bottle was very annoying while hiking. That said, I’ll likely use the handy bag to hold lighter weight items for easy access. - The pack size might run a little small. When sizing packs, I'm typically in-between a size medium and large. I found the medium size Flash Air 50 too small so I plan to swap it out for a size large.
Age:55–64
Yes , I recommend this product
Wesley
Long Beach, CA
1000+ miles and still going strong
1 week ago
I bought this pack online in 2024 after trying it on in the store and have used it for two PCT LASHes and a couple multi-day backpacking trips on the East and West Coasts. It's super lightweight with plenty of room inside for all my gear, including my BV475 bear can. The outer pocket fits any stuff I need easy access to like water filter, jacket, hygiene kit, etc. Each side pocket easily fits two 1-liter bottles. I modified one of the shoulder straps to better suit my water bottle holder but overall it's a pretty adaptable system. On a longer trip with 30-35 pounds it takes a bit of fiddling to get the fit dialed in but I made it work.
Age:45–54
Weight:150–175 lbs.
Height:5'10"
Yes , I recommend this product
campbub
Toledo Ohio
Nice ul pack that carries, and fits well
2 months ago
Over all this is a really good lightweight pack! Ive done a few extended hikes with it.. i have a few small gripes about it, but nothing major. I will start with the good, it fits very good to the body.. almost feels like part of you. The side water bottle compartments are nice to not have to take your pack off to get your water bottles. It can carry a pretty heavy load.. i did isle royal national park 5 night 6 days worth of food and it carried it no problem… the pack does what its meant to… Here are the improvements i would make to it. where the top rolls up, i would have made it strap down on both sides, to act as a type of compression strap. rei could skip the little pouch on the left harness, and give you a decent water bottle holder instead. If your on the fence about this pack dont be afraid to try it.. or the flash 55 ( its almost the same pack, just al little lighter)
Age:35–44
Weight:125–150 lbs.
Height:5'10"
Yes , I recommend this product
AJ Williams
Received free product
Chicago Illinois
Perfect lightweight but heavy duty backpack.
2 years ago
I upgraded to this backpack after years using a Kelty Coyote pack. It is insane how far the technology has come. Not only is this backpack lighter but it is way more comfortable. The back support is perfect and provides plenty of ventilation. There are plenty of quick access pockets all of which fit my iPhone. There is a pocket for a water bladder if you want to add one. The roll top design allows you To adjust to extend the pack size when you are carrying more gear. I cannot recommend this pack enough. It has done everything I have asked of it.
Age:25–34
Yes , I recommend this product
Grandpa Gator
Sacramento Ca
Noisy
8 months ago
I used this pack on the PCT from Mexico to Tahoe. I returned it as soon as I got off trail. The internal frame rubs on the water proofing on the backside of the material by the straps making very audible squeak right by your ears. Other hikers often mentioned how noisy my pack was. I got to enjoy this sweet sound for close to three months and around three million steps👎 Other than that I was pleased.
Age:55–64
Weight:150–175 lbs.
Height:6'0"
No, I do not recommend this product
Flying Mole
Pacific Northwest
The perfect pack for a 15-20 lb total weight pack!
11 months ago
I'm 72, and can't carry the weight that I could when I was younger, but I don't want to give up backpacking any time soon. I've lightened my base weight considerably over the past few years, but my 70 L backpack still weighed in around 5 lbs empty. A friend invited me to go on a weekend backpack up into the Gothic Basin, which is a fairly strenuous 12% average grade for several miles into a gorgeous alpine setting. I decided to finally spend the money for an ultra-lightweight backpack, and chose the REI Flash Air 50. Everything I needed fit easily into the backpack, and two days after purchasing it, I set out on the trail. IT. WAS. PERFECT! I was worried that perhaps the belt wouldn't support the load on my pelvis as well as my previous backpack, but it transferred mist of the weight to my pelvis and very little to my shoulders or back. Everything fit in easily, and I carried stove, food, water purification system, puffy jacket, sleeping bag and mat, tent, first aid, etc, with no problems regarding pack volume. I would probably have been just as tired going up without the pack, because the reduction of pack weight put me around 15 lbs total weight starting out with water and trekking poles. I also lived the cell phone pocket on the left front shoulder strap, which made taking photos very easy. The back pouch is roomy and easily fit my raincoat, pack cover and camp shoes. The side pockets were also roomy, and I put my water purification system/water (the GRAYL GeoPress system) in one pocket, and my bear spray in the other. The fabric showed no abrasions or damage, even though I had to scramble on some portions of the trail. This is truly an excellent pack!
Age:65–74
Weight:225–250 lbs.
Height:6'0"
Yes , I recommend this product
Hiking Hawkeye
Received free product
Woodland Park, CO
My new favorite backpack!!
2 years ago
This extremely light weight, 50L pack, with multiple pockets is perfect over overnight camping/hiking trips! I will use it on my next long distance hiking trip. It is the most comfortable pack that I have had on my back. It has plenty of pockets for easy access storage. Two water bottle pouches are located for easy access without removing the pack. The cell phone pouch and two zip pockets on the hip belt allows you to have what you need to hike for hours without removing the pack. I highly recommend this product!!
Age:45–54
Yes , I recommend this product
8 mile
Sub 2 lb pack from REI
1 year ago
Just completed my first 4 day trip. Phone pouch doesn’t fit my larger cell phone, but since the pouch is mesh, I wouldn’t use it for my cell phone anyway. When the top is rolled down and closed, the two hydration ports are exposed and open slightly. During rain, water will access the pack through these two openings. I purchased the large size and I wish the shoulder straps had another 3-6 inches of length. I have average size shoulders and wish the shoulder straps could losen a little more when putting the pack on or taking it off. Finally, water bottle pockets I can easily use while the pack is on. This pack is not designed for heavy gear carries. This is for people who have their gear dialed down.
Age:55–64
Weight:175–200 lbs.
Height:5'10"
SteveM
A bit disappointed
1 year ago
This is my first ultra-light pack. Was going on a 5 day desert hike and wanted to go as light as possible. I have been backpacking for many years including the JMT, Long Trail, Appalachian and many in Alaska. I like the pack overall, I loaded it with 25 pds (its upper weight limit) and carried it numerous days for a trial. It carried great! The suspension system felt good, was easily adjustable and really impressed me. The main compartment held everything nicely. The outer pockets are not as useful. Not enough elasticity or slack at the top of the pockets, making it difficult to get stuff in and out when the main compartment was loaded, especially the back outer pocket. the cords and straps for cinching gear are so lightweight and delicate, I broke two just cinching a pair of sneakers to the top. Ill take stronger cords and buckles anyday. No good if they are broken!
1 - 10 of 37 Reviews