Fastens to saddle rail and seatpost \n - Additional access to main body (5L compartment) via zipper on the drive side \n - May be rolled up to adjust volume \n - Mesh pocket with the zipper on non-drive side \n - PU coated splash resistant 600 denier Nylon \n - Water resistant polyurethane coating on all zippers \n - Fits 25.4 - 34.9mm seatposts