(Each 25 gram CO2 cartridge provides enough propellant for approximately 20 to 25 discharges of VetGun. )
Please note: The VetGun comes with a CO2 adaptor that fits a specific CO2 cartridge size: either the 25 gm OR the 90 gm. Be sure to order the CO2 cartridges that fit your gun. If you would like to modify your existing VetGun to accept another CO2 cartridge size, an additional adaptor may be purchased separately. No adaptor required for 14oz refillable CO2 tank.