Dual Head Combo Frame Pump and C02 Inflator is handy for a quick flat fix or keeping tires inflated while touring or long rides. Fits both schrader and presta valve tires. Accepts 12 and 16 gram THREADED cartridges. PSI gauge for accurate measuring. Use the hand pump or compressed air C02 cartridge. Mounts easily on your bike frame's braisons using the included bracket. Comes with one C02 cartridge.