Integrated into the Circuit is a 1.2 oz carbon fiber and delrin suspension hoop with an internal foam frame and an aluminum stay. The Catalyst steps up to a twin stay framesheet. The back panel is padded and the shoulder is contoured for comfort and support. There is a front shock cord and mesh pocket, and adjustable cuben fiber side pockets. For added convenience it's built with adjustable side/top compression straps, hipbelt pockets, pole retention loops, and complete with a rolltop closure.