Zerk 20 UL Daypack

NEW FOR 2026! Designed for a Viking, built for weekend warriors, this multi-sport day pack is ideal for long hikes and quick summit ascents. Now with increased modularity, new ultralight materials and additional convenience on the trail. Our new Zerk UL series truly 'Goes Where You Go'! Inspired by a Viking, used by weekend warriors. Meet the Zerk 20, the ultimate ultralight daypack. Built for grueling day hikes and challenging summits, the Zerk 20is the little sibling to our award winning Zerk 40L; loaded with all the features of the original but in a smaller, multi-sport form factor for weekend-slaying and personal bests. Developed in collaboration with The Real Hiking Viking as an out-and-back training pack to tackle the toughest terrain over long miles, this ultralight daypack will be your go-to for fast and light, all day outings. A Mountainsmith staff favorite! For this new addition to the Zerk UL series, we've added Zerk accessory compatibility with our Zerk 3L Loki Lumbar and Zerk 7L Toplid enabling you to turn this 20L daypack into a minimalist 30L backpack for hardcore overnights. We've also included modular compressions straps (x2) and field serviceable bungees; not only increasing your versatility on the trail, but also allowing you to strip the weight when minimalism is key.