Adattatore cilindro soda femmina TR21-4 a maschio G1/2 kit conversione per homebrewing
CO2 Regulator Adapter for Aquarium Fish Tank to Co2 Tank Adapter Convert Soda Water Maker Male G1/2 to Female TR21-4. Open the beer valve a little bit first, and then twist the soda bottle to the joint, so that there is less air leakage.