Use seamless welded technology, tarpaulin material and roll up design enables 100% waterproof. 22L capacity, Build in removable laptop bag, fits max 15 inch laptop. With mesh bottle bag at two sides. Multifunctional, can be used as bike pannier bag/commuter backpack/shoulder bag. Shoulder straps are hidden in the back bag which could be attached with rear rack. Open bottom zipper compartment, there is a helmet mesh bag inside.