The Seat Roll Up was designed around the essentials. Easily fit a 29″ tube, multitool, tire levers, C02, and nozzle with some room to spare. The external shock cord pocket is great for bringing a pair of gloves, a packable extra layer, or for shoving half a PB&J into. Easily attaches to the rails of most any saddle. Upgrade to an Austere Manufacturing Cam Buckle for a no slip experience, even on rowdy single track.