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Rated 5 out of 5 by from Best Backpack on the Market This pack is incredible! I am thru-hiking the Appalachian Trail and I needed a new pack about half way through my trip. I got this pack because it was exactly the size I needed for my summer gear setup, and it looked like it was a well thought out design. I couldn't be happier! This pack has already made it 600 miles and still feels as comfortable as ever. Whoever thought of the design with the fully opening main pocket and the brain attached to the main body of the pack is brilliant. I literally cannot think of anything bad to say about this pack. I definitely recommend this pack for both day hikes and anything longer. It is perfect for my thru-hike!
Date published: 2015-06-25
Rated 5 out of 5 by from Excellent Day Pack I recently bought this and used it on three hikes. It was comfortable, relatively cool, and carried everything I needed, including a larger than normal first aid kit, emergency bag, clothing, food, maps, guidebook, etc. I like the upper and lower external accessory straps that allow easy carrying of a coat or pad. Overall, it is excellent. I have one minor concern: It is hard to open the exterior hydration pocket and insert the bladder. Also, the hook does not hold my Camelbak bladders securely. Otherwise, I am extremely pleased with this pack
Date published: 2015-04-30
Rated 5 out of 5 by from My Best Carry On for All My Travels Awesome bag. I got the 40 in black. It passes ALL airlines' CARRY ON guidelines. The front of the pack ZiPPERS open for easy access like an upside down U that runs from the bottom left along the side to the top and then back down to the right. The ZiPPER can be open from the left or from the right. In your hotel room you set the bag down horizontally and you can unzip the front flap open to reveal all the contents of your bag. It's a NO NONSENSE bag. I travelled for 30 days in S.E. Asia w/my clothes, GoPro, and its accessories. I love this bag.
Date published: 2016-10-24
Rated 5 out of 5 by from Great day pack I use this pack everywhere I go. I take it with me when if I am on a day hike or just a day around town. I can easily fit a rain jacket, backup sweater and shirt incase the weather changes up on me. The upper zipper pocket (outer) is easily accessible and big enough to hold several small items while the zipper pocket on the inside conveniently flops down when you open the main compartment making it a great place to store valuables like a phone or wallet. The included rain cover was a nice surprise and comes in handy all the time.
Date published: 2015-05-26
Rated 4 out of 5 by from Compression straps would make this perfect I bought this to consolidate two older packs, one large Camelbak and an older Mountainsmith. It has the capacity of the Mountainsmith and the hydration capability of the Camelbak. I love the 4 zipper access, and it is really comfortable. The one thing that keeps me from giving this 5 stars is that it really needs compression straps. If you don't fill the pack, everything just slides to the bottom. Top and bottom compression straps would let you keep the load close to your back and keep a flat profile.
Date published: 2016-02-22
Rated 4 out of 5 by from Almost perfect This bag is almost perfect the only problems - and they were deal breakers for me: 1) no strapping to squeeze the main compartment down - things will bounce around in there when partially loaded. 2) the hooks that attach the sternum straps to the shoulder straps tend to bind on the fabric (similar to a zipper catching). The one I was looking at the strap was completely stuck, upon closer inspection, it was tearing the thin mesh shoulder strap material. I have a feeling they are all like this so be careful if you try to adjust the sternum strap up/down and it binds. Otherwise this is a super bag and has better features than most without looking so bakackerish when you're using it.
Date published: 2016-06-21
Rated 4 out of 5 by from Almost perfect - Still AMAZING for the price!!! I got this bag in Red because I love the color and also for visibility. I got several compliments on the look and style of it. This pack is very functional with several little pockets, spots for my trekking poles, jacket outside the top, and sleeping pad on the bottom. The little rings sewn in are convenient for things that need drying. I did a 3 day hiking/camping trip and this bag was great for my gear (hammock system rather than tent). This bag is also VERY sore spots on my waist or shoulders. The reason why I am giving 4 stars rather than 5 is because after the food was gone, I had some space and because there are NO internal nor external compression straps, the gear was weighted down rather than in the middle of my back...though it was irritating, it wasn't enough to make me dislike this bag. I still love it. However with internal and external straps this bag would have been PERFECT!!!.
Date published: 2016-07-08
Rated 5 out of 5 by from Perfect Pack for the money I recently purchased this backpack from REI in Anchorage AK. After completing a one day 23 mile hike on crow pass trail, I realize that it can't get any better than this. I had 32lbs worth of gear and water and don't have anything bad to say about the fit. It felt just as good as 30lbs can without causing any unusual discomfort. The full zipper proved to be convenient when I needed to get things out of the bottom of the bag and its easy to adjust the weight by tightening and loosing the various points of adjustment. The hiking pole inserts and straps worked flawlessly and came in handy throughout the day. Packing & organizing this bag was a breeze because of the full zipper and the cost is unbelievably cheaper than other major brand names. If your looing for a great day pack that's durable and won't cost you an arm & a leg then look no further. I would recommend this to anyone doing day hikes or light pack camping trips. Make sure you pay attention to the size when ordering online. I was able to get fitted in the store. I'm 6 foot 2 inches and 205lbs and the large fits perfectly, I have a long torso and was having trouble with proper fitting with some other packs. I can honestly say if you pay attention to the torso size you shouldn't have any issues.
Date published: 2015-09-08
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Questions & Answers

Is this pack an acceptable size as a carry on?

Asked by: lukec
Yes it is. 22" x 14" x 9" is considered the standard. This pack's dimensions are shorter in the length and width. Fully packed, the depth can be 10 1/2". So judicial packing will allow this pack to be within carry on size limits.
Answered by: REIservice
Date published: 2018-02-11

I'm 5'10", weigh 175lbs, athletic build and where a 32/32 pant. Could you make a guess whether I'd be a L or M for the REI Co-op trail 40?

Asked by: Hammmer
You can also go in to your local REI store. They have a measuring device and can take your measurements for you. I did this the other day, and I'm just at the high-end of medium/low-end of large. I'm about your size, but I have a long torso, apparently.
Answered by: FredM
Date published: 2017-07-25

Are the 2 straps up on the top third of the pack designed to carry a climbing rope externally? Is it recommended, or has it been known to be used for that purpose? Thanks!

Asked by: cristabul56
​The 2 straps on the top of the pack are meant to carry any gear you would like. A climbing rope can definitely be carried by securing it with those straps.
Answered by: REIservice
Date published: 2017-09-16

Is the pack good for laptop storage (15 inch laptop)

Asked by: Shelby
I have carried a 15 inch laptop as carry-on in this bag. Not great but works in the internal pocket. I had a sleeve on the laptop and it slid into the internal back pocket snugly.
Answered by: DaQi
Date published: 2017-09-02

Hi, can you give details on the pack material. What's the weight and type of Nylon. thanks. 

Asked by: jeffjeff
The Trail 40 is made from a 210-denier nylon.
Answered by: REIservice
Date published: 2017-07-25

Is there a hip belt extender available for this 40 liter backpack, or could a larger hip belt be optionally added? My son-in-law has a 54 inch waist and I'd like to get this for him.

Asked by: Tyler L
The hip belt is sewn-in and cannot be replaced. Unfortunately, we do not have a belt extender or can we recommend this pack be modified.
Answered by: REIservice
Date published: 2017-07-25

Can the straps towards the bottom of the bag be used to hold a small, lightweight tent like the Big Agnes flycreek ul2? I know it won't be too secure, but just curious!

Asked by: Vegezzi
Yes!! I have the womens version of this pack and big agnes tumble2 tent, and the tent can fit in the straps beneath.
Answered by: daniellem
Date published: 2017-07-25

Does REI have any plans to add side compression straps to this pack in the future?

Asked by: EAllen
​As of January 2018, we do not have plans to release this pack with side compression straps.
Answered by: REIservice
Date published: 2018-01-30
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