Quit losing time on your ride pumping your tires to pressure--this kit is the complete on-board inflation solution for the serious cyclist. Includes Microflate mini inflator, one 40-gram CO2 cartridge, and mounting block with Velcro(R) security strap. Cartridge fills two 26-inch mountain bike tires to 40 psi or three 27-inch road tires to 75 psi in seconds. Conveniently mounts anywhere on your bike. Fits both Shrader and Presta valves. Works with all threaded Genuine Innovations Co2 and Big Air products. Will not inflate beyond 75 psi.