How to Choose a Backpack
REI Co-op Flash 45 Pack - Men's
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Make your weekend trip a walk in the park with the REI Co-op Flash 45 pack. It has load-stabilizing tech, a contoured hipbelt, a breathable back panel and attachment points for all your gear.
Shop similar products- REI UpLiftâ„¢ Compression technology pulls the pack load up and in, closer to your center of gravity, to improve your balance and stability
- A 3D contoured hipbelt provides all-day comfort and stability
- An REI Packnitâ„¢ back panel with triangle foam increases airflow and breathability
- Water bottle pockets have secure snap closures and are positioned forward on the hipbelt so you don't have to remove the pack to grab your drink
- Removable top lid offers customizable pack volume
- Large mesh pocket in the front provides easy access to frequently needed items
- Attachment loops on the front allow ice axes, tools and more to be lashed on
- Hydration-compatible design
- 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
| Best Use | Backpacking |
|---|---|
| Frame Type | Internal Frame |
| Adjustable Torso Length | Yes |
| Material(s) | 420-denier ripstop nylon |
| Frame Material | Steel |
| Reservoir Compatible | Yes |
| Number of Exterior Pockets | 6 |
| Gender | Men's |
| Sustainability | 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.
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Most Helpful Favorable Review
Well thought out and comfortable!
Winterborn8 years ago
I typically use a pack around 35L but this pack was so comfortable when packed at its recommended max capacity that I decided to go with it. Its has thicker shoulder and hip pads compared to the last version and along with the uplift system so that is why it runs about 10oz heavier. Being a 45L it is a little bigger than i need but with all of the compression options I have no issues with gear sway. You can drop a reservoir internally or use the updated exterior water bottle pouches that rest in the crevice where the hip pads connect to the pack. They are simple to get to but a little tougher to get back in if you are using the soft water bottles. No real complaints about that as I am super stoked to have water bottle pockets that dont get compressed by straps or crushed entirely. The hip pockets stretch fairly well to accommodate a few small items . I use the zippered pouch for my REI 40L rain cover and it fits just fine. That cover fits the pack well too but it would be a little snug (but should still work) if the pack is filled to capacity. I have about 20 miles of use with this pack at a load-out of about 18-20 lbs and it is my favorite pack that I have used. A couple other details; you can easily go over the 45L with the expandable lid and large mesh pocket. The second hip belt pocket isnt zippered but could easily hold a phone or a couple snacks. The Zip pocket in the lid is large enough for my first aid kit, utensils, pillow, headlamp, and other small items along those lines. I am usually skeptical of store-branded products but I have had great experiences with multiple REI products and this one falls right in line with those experiences. Highly recommended if you're looking for a pack in this size range.
Winterborn
Ohio, United States
66 people found this review helpful
Most Helpful Critical Review
How to make a decent backpack worse
Customer7 years ago
Changes:
-widened the straps, = ok, if you really think it was needed
-reduced the size of that mesh on the back by splitting it into a central part and two side bottle pockets = ok
-top of mesh not clipped any more, but a hook instead (without ability to tighten it?!) = why, oh why?
-removed inside zippered pocket from the top compartment = why, oh why?
-removed one of the pole/ax attachments = why, oh why?
-added two "uplift" tighteners on the back (just two more things to break). = fancy for nothing
All in all: will return it.
-I need two attachment points for poles/ice axe
-I want to make sure that whatever I put inside the mesh is not going to spill
- do not need more flimsy plastic points to break (uplifts)
-liked putting IDs, phone and car keys in that inside zippered pocket
Customer
Leadville, CO
3 people found this review helpful
Customer Images
monkeyface
Worcester, MA, United States
Disclaimer - I Love REI
7 years ago
This is my third REI pack. I have a Trail 40 - big day pack, crazy useful. I also have a Crestrail 70 - total Dad Pack (3 kids? loading up 45 pounds? IT guys kick sand on you at the beach?) I went down to buy an Exos 58, but could not walk away without this Flash 45 as well which in every respect is superior except for volume. It's more comfortable, it's built more ruggedly, it's from REI, and it is cheaper. I'm keeping both but if I absolutely had to choose it would be this one. I'm not an ultralight packer - late November in New England and I had to pack this thing pretty tightly for three days. The Osprey will work better in winter if I'm on my own but honestly I'd take it back if I could.
Yes , I recommend this product
ZeroSix
Denevr CO.
10 day in Costa Rica
7 years ago
This pack was perfect for a 10 day trip around Costa Rica. It fit in the overhead without any questions. I brought everything I needed including a laptop 17in, Camel pack for day trips and a SLR camera.
Yes , I recommend this product
65BAJA
California, United States
Worked great for my 3D 2N trip into Desolation.
7 years ago
I have an older Atmos 50 pack that I really like but I was looking to go a little lighter. When I saw my local REI had this on the shelf I decided to try it. I'm glad I did. My all up weight with water was about 30lbs. A buddy and I went into Desolation Wilderness from Echo Summit for 3 days and 2 nights. The pack had enough room for all the camping gear and my basic fishing set up. Very comfortable and the straps stayed in adjustment as they should. After base camp was set up we packed the packs for a day hike up Cracked Egg. Pack was comfortable the whole time. Never felt like it was moving around too much or was going to throw me off balance.
Yes , I recommend this product
Winterborn
Ohio, United States
Well thought out and comfortable!
8 years ago
I typically use a pack around 35L but this pack was so comfortable when packed at its recommended max capacity that I decided to go with it. Its has thicker shoulder and hip pads compared to the last version and along with the uplift system so that is why it runs about 10oz heavier. Being a 45L it is a little bigger than i need but with all of the compression options I have no issues with gear sway. You can drop a reservoir internally or use the updated exterior water bottle pouches that rest in the crevice where the hip pads connect to the pack. They are simple to get to but a little tougher to get back in if you are using the soft water bottles. No real complaints about that as I am super stoked to have water bottle pockets that dont get compressed by straps or crushed entirely. The hip pockets stretch fairly well to accommodate a few small items . I use the zippered pouch for my REI 40L rain cover and it fits just fine. That cover fits the pack well too but it would be a little snug (but should still work) if the pack is filled to capacity. I have about 20 miles of use with this pack at a load-out of about 18-20 lbs and it is my favorite pack that I have used. A couple other details; you can easily go over the 45L with the expandable lid and large mesh pocket. The second hip belt pocket isnt zippered but could easily hold a phone or a couple snacks. The Zip pocket in the lid is large enough for my first aid kit, utensils, pillow, headlamp, and other small items along those lines. I am usually skeptical of store-branded products but I have had great experiences with multiple REI products and this one falls right in line with those experiences. Highly recommended if you're looking for a pack in this size range.
Yes , I recommend this product
zandergo
Boulder, CO
Great design, no frills, and solid frame
8 years ago
Used this pack on back-to-back weekends for backcountry skiing. Very impressed with the design, as demonstrated by the two water bottle sleeves nestled in the crux between the hip belt and pack. This is the first pack I've used of this size that makes grabbing and stowing a Nalgene easy without having to take the pack off. The fram of the pack is sturdy and a great fit (Medium, 5'9", 30" waist). The hip belt pockets are great for an iPhone, knife, and chapstick. Brain pocket is standard, front mesh stow pocket is great for easy access to layers, maps, etc. and the bottom-up cinch is a neat design to cut down on empty space or to get a snug fit to prevent gear from flopping around.
Yes , I recommend this product
Thedjwaver
San Antonio, TX, United States
Lightweight and Full of Features
8 years ago
Got this bag and as I wanted to go from a 70 L pack down to a more lightweight set up and the difference is amazing. The front pocket is large enough for more than just a pocket for your rain jacket. Ant the Back padding and support system rival those of more expensive packs.
Yes , I recommend this product
aFender
Boise, ID, United States
Huge improvement
7 years ago
First I bought the Osprey Atmos 50. It was definitely a good pack but after packing it for a couple days it felt painful. I went back to REI to check out some other packs and after loading and carrying four different packs I settled on this one because it felt SO comfortable. Maybe it just fits my body better? The bottom line is, it doesn't have all the bells and whistles and any "ultralight" pack will require some compromises, but this pack is so comfortable that I don't miss anything. Definitely worth checking out!
Yes , I recommend this product
DIYautotech
Tustin, CA, United States
Excellent pack by REI: Ive used many packs prior
8 years ago
I'm 5'10, 165lbs, small build but athletic. This pack in a Medium fit me perfectly. As for the pack itself, excellent execution by REI. I have tried on EVERY SINGLE HIKING PACK over 40L in REIs store, filled with roughly 25lbs of osprey weights. I can say that this pack is as comfortable than the osprey atmos variant! I just did a couple 15 mile day hikes with this pack, filled to the rim with 5 liters of water and unnecessary camping accessories, to bring my pack weight up to 33lbs. This is the UPPER LIMIT of this pack, but it still handled very well, no real shoulder pain or hip pain. You can definitely feel the aluminum frame flexing when the pack comes on and off at this weight, but once it is on your back, it is like a rock. The water bottle pockets are fantastic if you only plan to use them for water, and they accommodate REALLY wide bottles, these are NOT good if you plan to stack tent poles or other accessories in them. The stretch pocket in front holds alot of gear, and it's nice and accessible. The brain has one zippered pocket that is ample size, and the pack is perfectly sized for an Osprey 3L water bladder (what I used). The compression straps do an ample job of pulling the load into your body. The shoulder staps and hip belt are stiff at first but definitely soften up. I found this pack to be insanely comfortable despite its hard foam appearance, and I am considered "boney". This is a great sized pack for a 1-2day adventure for those who are not exactly ultralight, but can definitely span to a 2-3day pack if you are effective with your planning and packing. The left hip belt pocket holds my iphone7 with otterbox defender case, the right pocket is zippered and holds plenty of snacks. I love this pack! It rocks! BUY IT.
Yes , I recommend this product
Larry
Massachusetts
Very Comfortable Pack
6 years ago
Well, I've had this for a year now and have used it on 16 trips. Generally, I go out for 1 or 2 nights, but I had no trouble with capacity on my 4-day hikes. This is relatively light (46 oz) compared to my old Lowe Contour IV. I spent hours in the REI store and paraded around with numerous fully loaded packs, including Deuter and Osprey models, and this was the most comfortable. This pack was part of my plan to lighten up my kit. Fully loaded with food, water, fuel for a 4-day trip I am at about 25 lbs. I have no trouble getting it all in the pack during the summer. However, with the larger sleeping bag and extra clothes, it gets tight with my late fall loadout. Fortunately, it has a floating lid so I can get it all in there. I have neck issues and need to transfer the weight to my hips. That is the primary reason I needed this pack versus one of the "ultralight" packs. It is the most comfortable pack I've used. The material is lightweight but it is holding up well. I am careful not to throw it around like I did with my old Lowe, but I've been through thick underbrush with no issues. I expect I will have this for years to come. I especially like that I can reach water bottles while hiking. I also like the meshing back pocket but I wish it was a little bigger. I also like the hip belt pockets, but wish they were bigger as well. Anyways, I am very happy and hope to use this for many years to come.
Yes , I recommend this product
BlueRidgeScout
Washington, DC, United States
Lightweight, solid support
8 years ago
I purchased this pack with my dividend about a month and a half ago. I've since taken it on several overnighters and, without a doubt, this bag packs a punch, especially for the low price. It ditches extra weight by getting rid of organizational features that are common among mid-range packs, but honestly, I didn't find myself missing the bells and whistles. It has everything you need and nothing more. The main compartment is undivided and top-loading, but is actually quite spacious - I'm able to fit my 22 degree synthetic sleeping bag, pad, bear canister with stove inside, tent, and jacket/baselayers within the body of the bag with room to spare (I could probably get a fleece bag liner in there if I really wanted to). The brain of the pack is a wee bit small but sufficiently contains everything I need it to, and what doesn't fit slides nicely into the stretch mesh pocket on the front. The uplift compression system appears to do its job as advertised. Meanwhile, the side-pockets are sewn into the belt. which leads me to my only gripe: the pockets do not close tightly without a nalgene or large bottle inside, so you can't really use them to stow tent poles and other slim objects inside. But, this feature also makes it easy to reach a stowed water bottle, so it's a plus and a minus. All the while, it carries like a cloud. I didn't even think I'd like the off-white color but that's grown on me too. If you're looking for a small, lightweight pack that gets the job done, I'd definitely recommend this one.
Yes , I recommend this product
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