How to Choose a Backpack
REI Co-op Mars Pack
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With loading options and ultra-adjustable suspension, our new internal frame pack handles backpacking in any season on any planet!
Shop similar products- Dual access to pack: top loading plus a horseshoe zipper front panel opening, like a duffel, gives complete view of contents
- An REI exclusive, back panel features a new quick-adjust torso system that is light and durable providing 4 inches of adjustment per size
- Removable top lid doubles as a hip pack for shorter jaunts when you don't need a lot of gear
- Zippered pocket under lid stores maps and keys, plus doubles as a hydration pocket for reservoirs
- Front panel features an oversized zippered pocket protected with a waterproof zipper for storing often-used gear
- Internal sleeping-bag compartment is created by a zippered divider, separating it from gear and clothes in the main compartment
- Both sides feature dual accessory pockets that are sized to fit gloves, water bottle and more
- External mesh side pockets hold water bottles, energy bars and other essentials you want close at hand
- Concave head pod at the top of pack frees up your head for ultimate freedom of movement
- With seven buckles, the streamlined compression system lets you cinch and strap down loads for jostle-free carrying
- Waistbelt features a quad-buckle with four webbing cinches for precise adjustment to hug the waist
- Shoulder straps feature ultra-breathable BROCK Foam™ giving exceptional cushioning and cooling comfort, on and off the trail
- Main compartment's extension/storm collar provides an extra 400 cubic inches of volume
- 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
Specification for torso/ waist and hips/ base volume and average weight are as follows:
View all REI Co-op Backpacking Packs- Medium - 15-21 in. / 28-54 in. / 5,100 cu. in. / 84 liters / 5 lbs. 13 oz.
- Large - 17-23 in. / 30-60 in. / 5,300 cu. in. / 87 liters / 6 lbs. 2 oz.
| Weight | 5 lbs. 13 oz. |
|---|---|
| Fits Waist/Hips | 28 - 54 inches |
| Number of Stays | 2 |
| Number of Exterior Pockets | 6 + main compartment |
| Best Use | Backpacking |
| Fits Torso Length (in.) | 15 - 21 inches |
| Material(s) | Nylon |
| Frame Material | Aluminum |
| Sleeping Bag Compartment | Yes |
| 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.
