Food Grade Material, Stainless Steel Material for Keg Coupler Adapter, Food Grade Silicone Material for the O-ring Gasket Easy to Use, the Keg Post Connect the Ball Lock Disconnect, Work with Beer Keg Coupler Directly Clear to Identify, the Gas Keg Coupler Adapter has a Deep Subtle Etched Line, the Liquid one has no Line Makes it possible to seamlessly switch between your ball lock corny keg and a commercial Sanke keg in seconds Carbonation caps can carbonate a number of beverages, including beer, soda, water, and juice,also can clean your beer line and to counter pressure bottle fill PET bottles