Description
The Altruist Hydration Pack is part of our Pure Mountain Running line, designed for athletes who move with purpose through environments that constantly test both gear and resolve. Built for long efforts where reliability matters most, the primary body utilizes challenge cloth — a three-layer composite combining high-density polyester, UHMWPE fiber reinforcement, and a protective polyurethane film. The result is a fabric that delivers exceptional abrasion resistance while remaining remarkably lightweight, ready to withstand sharp rock, dense brush, and the relentless friction of miles in the mountains.
Supporting this foundation is our EnduraMesh XT, a true 4-way stretch mesh engineered to move naturally with the body. Where conventional stretch materials fatigue and fail, EnduraMesh XT integrates Nylon 66 for structural strength with 30% UHMWPE fibers, a material rated up to 15 times stronger than steel. This creates adaptive storage that maintains its integrity over time, ensuring secure carry and consistent performance through demanding conditions.
Every fabric choice in the Altruist reflects a commitment to durability, movement, and trust — because when the terrain pushes back, your gear should remain the one constant you can rely on.
Recommended Use:
The Altruist is designed for multisport athletes and endurance adventurers who need a versatile, high-capacity pack built to handle everything. Ideal for ultrarunning, adventure racing, mountaineering, and long backcountry adventures where carrying a variety of gear is essential. Perfect for athletes who demand fast access, durable construction, and all-day comfort across unpredictable terrain and changing conditions.
Details:
• 28-liter roll-top design built for multisport and endurance athletes
• Durable construction with premium materials for rugged, all-condition use
• Massive side pockets fit all UltrAspire hydration options and allow fast gear access
• Externally accessible, insulated reservoir sleeve for efficient mid-effort refills
• Large quick-stash outer pocket with compression for secure load management
• Anodized aluminum buckles provide reliable attachment for poles, ice axe, or hose management
• MaxO2 sternum system with adjustable toggle buckle for custom fit and breathability
• Front harness includes a zippered bottle pocket with weather protection
• Layered zippered pocket at the fingertips for quick-access items
• Sweat-proof lined phone pocket keeps electronics protected
• Dual zippered top shoulder pockets for additional organization
Specifications
Fit: SM/MD: Waist 27″-38″ Torso 15.5″-18.5″, MD/LG: Waist 29″-42″ Torso 17.5″-20.5″
Sizes: SM/MD, MD/LG
Color: White/Black
Hydration Included: Not Included
Bottle Compatible: UltraFlask 550 Hybrid Bottle, Softflask 300/500/625/800/1L
Capacity: 1708 cu in (28L)
Weight: 2 lb 1 oz w/frame (935g), 1 lb 14 oz w/o frame (850g)
ALTRUIST CAPACITY & DIMENSIONS
Main Compartment Capacity: Approx. 23L
Total Pack Capacity: 28L
Main Compartment Dimensions (fully loaded with one full roll):
- 60 cm tall
- 23 cm wide (measured at center of pack)
- 17 cm deep (measured at center of pack)
Exterior Storage:
- Front side pockets: Approx. 1L each
- Waist pockets: Approx. 0.5L each
- Rear bottle pockets: Approx. 1L each
- Rear stow pocket: Approx. 1L depending on main compartment load
Dandelion Dilluvio-Scott (verified owner) –
Like all the products in the Pure Mountain Running line, the Alturist was created with the adventure mountain athlete in mind. Durable textiles and thoughtful features make this an excellent option for alpinists who want to run the trail sections of of the approach.
Erik Hamilton (verified owner) –
Another great offering from a line of super comfortable, ultra durable hydration packs. I’ve taken my Altruist on several smaller hikes and mountain runs but all in the name of testing, I loaded the Altruist with 2x 800ml and 1x 1-liter soft flask, which could be swapped easily using the bloddle hose attachment.
28miles with 9750ft climbing, trail running and rock hopping and this pack was still riding very comfortably/ no rubbing anywhere. The added waist belt helps to keep the load in place nicely; a symmetrical set up of (many, many) pockets allows gear, snacks, trash, phone, etc all stay organized. The rolltop is a super feature, allowing the pack to compress onto the clothing and gear inside, to further prevent jostling. I will be using this 28L for the Jigger Johnson 100mi race in the White Mountains and will be adding a 2L bladder in addition to large soft flasks – the pack has ports to run and secure all the hoses, alternatively they fit nicely in the mesh pockets on either side externally as well. Great set up, lots of places to attach cordage or tie things to the pack if need be. I stowed a set of fold up poles to the bottom of the packs exterior, easy to synch down or grab on the fly without being a contortionist. One of the best features is one of the smallest – the zippered pockets on top of each shoulder strap are great for keys, lip balm, gels etc.