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  • Women-specific fit involves contoured foam in the harness and hipbelt
  • U-shaped panel with 4 zipper sliders offers quick access to gear and total access when fully open
  • Spring-steel perimeter frame provides load support while also allowing the back panel to conform to your back
  • Inside the main compartment is a mesh side pocket and a back pocket with its own bungee compression system
  • Included raincover stows in its own zip pocket
  • Padded, mesh-covered straps, belt and back are cool and comfortable
  • Side mesh pocket with elastic closure; outer pocket for phone or sunglasses; sleeve for hydration reservoir (sold separately)
  • Top has a zippered pocket on the underside for your keys and valuables; zippered hipbelt pockets let you access snacks and other essentials as you hike
  • Special fasteners on the back hold trekking-pole tips down low and pole shafts up high
  • Forward-pull hipbelt design makes adjustments quick and easy


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Best Use Hiking
Bag Style Backpack
Frame Type Internal Frame
Gear Capacity (L) 40
Gear Capacity (cu. in.) 2,441
Weight 2 lbs. 13 oz.
Weight - Metric 1.28 kilograms
Fits Torso
16-18 inches
17-19 inches
Fits Waist/Hips
26-38 inches
28-40 inches
Material(s) Nylon
Frame Material Perimeter spring steel
Pack Access Panel
Number of Exterior Pockets 6 + main compartment
Hipbelt Yes
Raincover Included Yes
20.25 x 13.125 x 10.5 inches
21.6 x 13 x 10.5 inches
Gender Women's
Rated 5 out of 5 by from Comfortable and fits everything for a dayhike For dayhikes, this pack fits everything I need and is a pleasure to wear. My previous daypacks hung off my shoulders and made my back hurt. This pack is easy to adjust so that it balances squarely on my hips. One minus is that it's difficult to squeeze my 3-liter Platypus in the back external reservoir; it does fit, though. I've gotten the hang of widening the opening with one hand and pushing the bladder down with the other. At home in the city, I take the pack to the supermarket when I go out on foot or take the bus. It fits a lot of groceries, and I can feel like I'm training for my next wilderness adventure. Absolute right purchase for me.
Date published: 2016-05-30
Rated 4 out of 5 by from Great without hydration bladders I loved this pack in the store. I had it fitted by an REI salesperson and it felt great. The hip pockets are a perfect size, I can fit my Iphone in the pocket with room to spare (the smaller 6, not the phablet size). But the external pocket for the hydration bladder is really tight. When I squeezed the bladder inside, it deformed the back panel so it didn't fit well. Trying to fit one inside in the inner pocket is okay, but it is a little too small to fit it well. I think this is a great, very comfortable pack if you aren't looking to use the hydration bladders. One of my favorites. But if you are going to use hydration bladders, I would consider another pack.
Date published: 2015-11-12
Rated 4 out of 5 by from Perfect hip belt! Needs side compression straps. I bought this for an upcoming 2 week trekking trip in Nepal. I packed it with a sleeping bag, fleece, puffy vest, toiletries, microfiber towel, iPhone/charger, external battery, SteriPen, and DSLR camera and batteries. It came out to about 15 pounds. One of the reasons I chose this pack was the hip belt pockets. They are big enough to hold an iPhone 6 and case. The other pockets provide adequate organization as well. The only downside to the pack and the reason I will most likely return it is that it has no side compression straps. The load pulls down instead of carrying close to my back. When fully packed, the load dips below the hip belt and onto my tailbone.
Date published: 2017-01-31
Rated 3 out of 5 by from Good pack for the cost I purchased this pack for a recent hiking trip and was very pleased with its storage, features and cost. My only complaint with the pack is that the hydration pocket is extremely difficult to use. I tried every possible angle of wedging my 2L bladder into the pocket but it was impossible (even when the bladder was empty). I ended up putting my bladder into the back-most inner pocket and weaving my hose through the main zipper. Then, I connected the two zippers spanning the zipper gap with a carabiner to ensure that the backpack didn't come unzipped while hiking. Even with this flaw, the backpack was a great value and offered a lot of storage space.
Date published: 2016-01-03
Rated 2 out of 5 by from Designed by the devil himself. Good: lots of pockets, zipper access to the bottom of the bag, and plenty of space. Bad: -It was a pain in the butt to get my 1.5 liter camelbak bladder into the space for it--and I know that size is on the smaller end so I can't imagine trying to get a bigger one in it. And this is when the pack was empty. When it was full, it was near impossible. -Maybe it's just my body but I hiked with a not-so-full pack and my less meaty parts were definitely sore for a few days following (collar bones, lower back, hips). -When the top is cinched down, it is a pain to zip and unzip in that area. I gave it a few chances. Boo, it's going back.
Date published: 2016-03-05
Rated 5 out of 5 by from Love this pack I bought this pack a month ago for day hikes and weekend backpacking trips. I'm 5'3" and a lot of bags overwhelm me in the 40 L size, but this one doesn't (I bought the small size). I like the color, light weight feel, multiple compartments and the material on the back of it doesn't get too hot while hiking in the summer. I've used the rain protector 3 times in the last month and it has kept the pack dry as well. It's comfortable to wear and I especially like the side pockets on the hip straps for easy access for my small camera, chapstick, and inhaler. The only issue I had was some of the tassels that attach to the zippers were missing when I bought it so it's not as easy to pull closed (easy fix, but I haven't got around to it yet). I definitely recommend this bag.
Date published: 2015-06-24
Rated 5 out of 5 by from Great Pack! Got the REI Trail 40 in April 2015 after I had finally come to terms with the fact that my beloved old and heavy day pack was too worn out to use anymore--I had hiked all over the Cascades, Sierra, as well as Europe--and I didn't want to give it up. However, the transition was easy because I LOVE this pack! This particular model does not rub me in the sacrum as other similar models from other brands did. I've taken it on about 10 hikes and it has done really well. My only 2 small gripes are: I would prefer to have a quick access outside strap to hold my poles (the 2 single pole holders is tedious to use and don't really have an upper strap); also the belt pockets are way far back and hard to reach--but on the other hand, my arms don't rub against them either. I heartily recommend this.
Date published: 2015-08-08
Rated 5 out of 5 by from Great pack I purchased this pack recently and really like it. I am a field biologist and use it for working in the field, as well as carrying my laptop to the office and for trips as a carry-on. It has all the things I was looking for, including the pockets on the hip belt big enough for an iphone, an easily accessible pocket on the front of the pack, a sleeve for a bladder (which I have not tried yet--seems like it might be a little tight to get in there though), a rain cover, and is panel loading. All in all exactly what I had been looking for. I'm 5'2, 115 lbs and the size small was great.
Date published: 2015-10-01
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I have a question about the oregano color. On my screen it looks like what I can only describe as baby poo. Is there a chance that it's really more of an army green or a kakhi? Also: how often/at what time of year do you typically switch up the colors?

Asked by: Slidemars44
I'd say it's a mix btwn army green and khaki. It's definitely in army family of colors though. My husband wants one!
Answered by: D Lee
Date published: 2017-04-02

What is the color of the accents on the pack? Is it orange? Or more pink? Could you please tell me the exact name of the color?

Asked by: Eli226
I would call it salmon
Answered by: theonlykanga
Date published: 2017-03-08

Will this fit under the seat in front of you on an airline. Jet Blue let me shove it under, but will Frontier?? I don't want to pay $70 to travel to Vegas this weekend. Meed gambling $$

Asked by: Scooterpam
This pack measures 21 x 13 x 10.5 inches, or 44.5 linear inches. Most airlines require a piece of carry-on luggage to be no bigger than 45 linear inches (L + W + H) to meet carry-on size restrictions. This can vary, so please check with your airline to confirm their luggage requirements and to check if it will fit under the seat.
Answered by: REIservice
Date published: 2017-05-21

I like the pack colors in the video. Are the colors being sold?

Asked by: venushiker
The colors black sapphire and cavern cave are no longer available. We do not plan on restocking these colors.
Answered by: REIservice
Date published: 2016-09-16

Will this fit a 3 L bladder well? 

Asked by: Christaeileen
​This pack accommodates a 3 liter reservoir.
Answered by: REIservice
Date published: 2017-04-21

Is there any hope of new colors being offered of the Women's Trail 40L pack in the near future?

Asked by: jkbowles
​As of February 2017 there are no plans for new colors to be offered.
Answered by: REIservice
Date published: 2017-04-10

I ordered this pack and the sleeve for the hydration pack seems really tight. Can you really squeeze a full 100oz hydration pack into the sleeve when it's full? The top opening is the only way to get the hydration pack in, correct?

Asked by: hiker74
A full 100 oz. reservoir will fit in the sleeve. The top is the only opening.
Answered by: REIservice
Date published: 2016-11-15

Hello, Can you please tell how to choose the size? I have a lookout-40-pack-women that fits me well. Thanks Catalina

Asked by: Catasegura
The size you choose is based on your torso length and your waist circumference. See the link below to find out how to measure torso length: The small has a torso of 16" – 18", medium 17" – 19". The women's REI Lookout 40 had a torso length of 16" – 18".
Answered by: REIservice
Date published: 2017-01-22
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