Air Venturi CO2 bulk-fill adapter Fits Umarex EBOS Screw the adapter into the CO2 port of the EBOS With the adapter securely attached, screw a paintball CO2 bulk-fill tank (12 oz. recommended) into the adapter (see note below) Extremely economical...more shots, less money EBOS buttstock cannot be attached when you use this bulk-fill CO2 adapter Does NOT void the manufacturer's warranty * NOTE: The paintball tank valve will immediately open when it's completely screwed into the adapter. Make sure the adapter is tightly/securely installed in the gun before the tank is tightened down.