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Mountainsmith - Zerk 40L Phantom Backpack

Mountainsmith Zerk 40L Phantom Backpack

Temporarily Out Of Stock

Don't get too bummed. This item is on the way and will be available for purchase as soon as it rolls into the warehouse.

Can't wait? Consider one of the other Weekend Packs (3000-4500 cu in) we have in stock.

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Tech Specs

100D nylon HT, 200D Spectra Double
40L (2440cu in)
atilon foam
Shoulder Straps:
extra wide perforated EVA
Waist Belt:
Hydration Compatible:
2 large side water bottle, 1 front mesh, 1 mesh side stash, 4 mesh shoulder straps
Gear Loops:
side SR buckles
Weight Capacity:
18.5 x 11.75 x 5.75in
Claimed Weight:
1lb 12oz
Recommended Use:
backpacking, ultralight backpacking
Manufacturer Warranty:

Zerk 40L Phantom Backpack

The Zerk 40L Phantom Backpack is built to have your back while navigating ridges, scampering up faces, or perusing the desert. This versatile pack uses wide shoulder straps to evenly distribute weight across your torso, in combination with a traditional roll-top design that lets you stuff in that extra piece of gear with ease.

  • Through hiking pack ready for casual and involved missions alike
  • Stiff foam and breathable mesh combine for a comfortable fit
  • Ultra-wide shoulder straps evenly distribute weight on torso
  • Roll-top design provides expansive storage and reliable closure
  • Large side pockets can be stuffed with layers while on the move
  • Outer mesh pocket offers effortless access to gear and snacks
  • Removable waist belt lets you minimize weight if you so choose

Mountainsmith Zerk 40L

    Co-designed with The Real Hiking Viking, a renowned thru-hiker with thousands of hiking miles under his belt, the ZERK 40 pack stands alone as the ideal combination of weight, durability, comfort, and accessibility.

    Mountainsmith Zerk 40L