This waterproof pack has 1220 cubic inches of space under its durable panels. Equipped with removable shoulder and waist straps, it can be carried courier style on or off the bike. The shoulder strap connects to the large D-rings at each end of the pack and the waist strap connects to two fold-away buckles at the corners of the mesh pocket. It works as a tailbag, with included straps that attach and remove easily via four quick-release buckles. The zipped mesh pocket on the back panel stores shoulder & waist straps when attached to your bike. Add over 600 more cubic inches of space by attaching a US-10 to the top of the US-20, or add 1220 more cubic inches of space by attaching two US-10’s to the sides of the US-20 — for a full 2440 cubic inches. 15.7"×10.2"×7.5".