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Hyperlite Mountain Gear
Prism 40L Backpack

5 out of 5 stars
2 Reviews


Size Chart


Why We Like The Prism 40L Backpack

The mission is grand, and the conditions are bleak, but the Prism shares out grit. We stuff all our gear into the cavernous body and pull the 4 compression straps tight. We slide the hip belt out, so it doesn't interfere with our fully racked harness, while the low-profile lid keeps our rope at the ready. Whether we're climbing a mixed route or postholing through knee deep powder, the light, rugged construction moves with us, not daring to challenge our stability more than the mountain already is.


  • Lightweight pack for austere alpine pursuits
  • 40L capacity for gear intensive days and weekend-long expeditions
  • Removable contoured aluminum frame sends weight to the hip belt
  • Padded back panel and suspension system give a comfortable carry
  • Removable hip belt features 2 gear loops and 2 ice clipper slots
  • Rugged, waterproof materials keep your gear safe and dry
  • Extendable drawstring closure offers more space for longer missions
  • Dual side compression straps double as an A-frame ski carry system
  • Item #HMGD00E
40L (2441cu in)
removable contoured aluminum frame, plastic stiffener, 0.25in foam back panel
Shoulder Straps
Dyneema, 0.375in closed-cell foam, spacer mesh, adjustable sternum strap (with whistle buckle)
Waist Belt
removable, dual-density Dyneema, 2 gear loops, 2 ice clipper slots
drawstring top
1 compression front, 2 side sleeves (with drainage holes), 1 floating lid (removable)
Gear Loops
daisy chains
Ice Axe Carry
2, bungee tie offs
side straps, floating lid
Weight Capacity
11 x 35in
Claimed Weight
1lb 13.1oz
Manufacturer Warranty
1 year

Overall Rating

5 based on 2 ratings

Review Summary

1 Stars - 0 reviews
2 Stars - 0 reviews
3 Stars - 0 reviews
4 Stars - 0 reviews
5 Stars - 2 reviews

Fits True To Size

Screen reader users: the following list provides a visual scale to illustrate the product fit. Please refer to the heading above for the fit type in text.
Runs smallTrue to sizeRuns large

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5 out of 5 stars

July 7, 2022

The perfect mountaineering pack

I've put it through the wringer
Size Bought:
5' 9"

‘Shoot.’ It was three days before I was to embark on a big mountain traverse and my mountaineering pack was nowhere to be found. I have a tendency to lose items in a move, but it’s usually a charger here or a sock there. Not an entire backpack! I hastily researched what would fit my needs…one item in stock. Before I could even think about how much money I needed to transfer from savings, a tracking number arrived in my inbox saying the item was due the following day. When the package arrived, I was sure I had been duped by the shipping company. There’s no way a backpack is inside this box, it’s far too light! As I opened the package, there lay the HMG Prism. The perfect mountaineering pack, one that takes the color of whatever terrain you’re in until it’s too dirty to be recognizable. When we got to the trailhead, you could barely make out the restroom sign through the hazy sea of mosquitos swarming the area. With our brains focusing 85% of their energy on the constant blood-sucking annoyance, we hastily overpacked everything we purchased (enough food to last three times the length of our trip). Luckily for me, the weight carried in food was easily offset by the ounces shaved in developing the HMG Prism (without sacrificing comfort). After a long approach in, we rested our feet in the nearby lake while filtering fresh snowmelt. Across the water a Marmot lay sunbathing, earning its golden coat. As we tucked into our sustainably-sourced down-filled bags and rested our heads on our rugged packs, I could hear the cams in my bag compressing. They had a soothing rhythm to them, like a metronome, which is odd given they’re inanimate…then it hit me. That sunbathing Marmot wasn’t relaxing, he was casing the joint. I quickly lifted my head and a bright beam tracked his furry coat into the bushes nearby. That’ll teach him, I thought. It wasn’t until morning that I realized he had already executed his plan long before I scared him off. My sunglasses were nowhere to be found. My hat was ridden with holes. My hiking poles were cork-less. My pack…unbroken. The HMG Prism fought off the marmot canines, a true sign of its toughness. This pack is light enough to think it’s been stolen, comfortable enough to overpack, and strong enough to outlast the jaws of an apex predator.

jacp681172 j
James FGearhead
5 out of 5 stars

July 7, 2022