This carbonation cap is a screw-on cap with an integrated Cornelius ball lock fitting. It is designed to fit onto most soft drink PET bottles. The carbonation cap is highly effective method to add and maintain carbonation in beverages for extended periods of time. Made from 304 Stainless Steel the carbonation cap will last years of use with virtually no maintenance. With this cap you can simply fill an old PET bottle with cold liquid of your choice and carbonate by connecting your gas ball lock disconnect. Make your own soda water, carbonate beer, or even make your own soft drinks.