La Sportiva Challenger 28: a modular alpine backpack
The roll-top pack expands from 28 to 32 liters and uses Ultra 400 and Ultra 200 fabric.

La Sportiva’s Challenger 28 is a modular backpack for mountaineering and ski touring. Its roll-top closure expands the capacity from 28 to 32 liters, with side-access zippers for reaching equipment without opening the top. La Sportiva’s official specifications.
The pack combines Challenge Sailcloth Ultra 400 and Ultra 200 fabric with a PFAS-free C0 water-repellent finish.
Removable components include a thermoformed back panel and hip padding. The carrying system has adjustable shoulder straps, a sternum strap with a whistle and a double-D waistbelt. External attachments accommodate a rope, helmet, ice tools and skis.
The US product page lists 780 g minimum weight and 1,200 g fully equipped, in M/L. These figures describe different configurations of the same pack.