Mangrove Jack's Carb Line Clean&Counter Pressure FillerThis Pressure Filler Cap makes transferring beer to a bottle easy! If you keg your beer and want to take a few bottles for you to drink or your friends to try, this is the perfect piece of equipment for you. It can also be used to carbonate your beer or water or used to clean your beer lines. This fits both the black liquid and grey gas ball lock disconnects and has a barbed tail that fits 6mm tubing if you wish to use this when filling bottles.