for CO2 Cylinder Tank Refill Adapter Fill Station. Thread for TR21x4, Allows to use most for Machines. With Quick Disconnect Connector. This Item Use for / Soda Club To External Tank Cyclinder Connect.Like 5lb, 20LB or 50lb commercial CO2 tanks. This item can't fit Australia or New Zealand for bottles. Our Adapter Don't Work Residual Pressure Valve (RPV valve). Please don't disconnect the quick disconnect under pressure, it be blowed out the o ring in quick disconnect(female QD),Use bleed valve drain residual pressure. How it works: Screw the adapter to a larger CO2 gas cylinder. The empty for cylinder is screwed into the fill adapter. Connect quick disconnect. Open the valve of the large gas bottle. Wait for the cylinder is completely fill, about 30 sec. Close valve of the large gas bottle. Opening the Vent bleed valve screw to drain residue remaining gas. Unscrew the CO2 - done. Thread To Big Bottle: W21.8-14 W21.8-14(DIN 477) connector Compatible With M22-14, Common in , JP, UK,