This large tail bag is capable of holding a full-face helmet when expanded. Made of UV-treated Tri-Max® ballistic nylon. Comes with necessary mounting system that is usually sold separately, waterproof slip-over covers for bad weather, and un adjustable shoulder strap. Snaps right to the saddlebags when used together. Holds 29.83 liters (38.78 liters expanded.) Main compartment measures: 14"L x 13"W x 10"H (14"L x 13"W x 13"H expanded).