Mountainsmith Zerk 40 Phantom


Through a load of hours, miles and beers, plus one big old beard, Mountainsmith have produced the incredible Zerk 40 Phantom! Developed by the Real Hiking Viking this Zerk 40 stands alone as the perfect combination of weight, durability and comfort with true accessibility too.
  • Features

    1.5” removable waist belt

    Large main compartment holds up to 40 litres of gear

    Roll top closure with side compression SR buckles. Opposing SR buckles for self-closing roll top

    Side compression straps for securing load throughout entire pack

    Large side water bottle pockets with angled opening to easily remove and insert items while on the go

    Expansive front mesh pocket for hauling bulky gear

    Large mesh side stash pockets with angled opening for easy reach

    Reflective screen printing and cord loops for low light visibility

    Front cord loops can be configured with bungee cord (included)

    Removable interior laser cut frame sheet (EVA Atilon) allows for rigidity and airflow

    Extra wide shoulder straps with adjustable sternum strap (includes safety whistle)

    4 Large mesh front pockets on shoulder straps (2 per side)

    EVA foam padded shoulder straps

    Removable accessory over-top webbing straps with SR buckle closure

    Front panel bungee attachment system

  • What We Think

    Co-designed with The Real Hiking Viking, a professional 'hike-really-long-distances-really-quickly', the ZERK 40 was born out of a need for an ultralight pack that can withstand the thousands of miles per year that The Real Hiking Viking already covers. Mountainsmith wanted to make sure that it would allow him to go farther, to hike longer, and to work more efficiently on the trail. Over the course of 2 years of development, the ZERK 40 went through 4 iterations and over 5,000 miles of testing on the Wind River High Route, the Colorado Trail, The Tetons, and more.

  • Specifications

    210d EXTREEMA Recycled Nylon Ripstop (UHMPE)

    Recycled 210d nylon SD oxford

    Nylon 100D x Span 840D stretch mesh

    47 x 30 x 14.6 cm (18.5" x 11.75" x 5.75")

    Waist belt max 122 cm (48")

    Torso range 41 - 48 cm (16" - 19")

    40 litres with fully extended collar

    32 litres with roll-top compressed

    Up to 14 kg

    822 g with accessories. 765g without accessories