The Canadian Large Field Pack/Framed 1982 pattern is constructed of Cordura Nylon that withstands a lot of abuse. The top of the pack is accessible via a zippered closure on top for easy access to the main bag. The main bag is 2200 cu.in with a map-pocket for smaller items. The side pockets are roomy and allow a pair of skis to be mounted underneath them. With a large main compartment, top-loading and three very usable (Large) accessories exterior pouches and a top compartment, you don't have to leave anything behind. The frame is incredibly lightweight with fully padded shoulder straps, lumbar pads, and Fastex hardware. Large enough for cold weather treks, when the gear is voluminous and lightweight enough for the summer, this pack is such a great deal. The pack can be downsized easily to use it as a smaller pack, with its built-in compression straps. Over 3000 cubic inches of storage.