Do you have old style 500 series Perlick faucets that you would like to use with the Tapcooler Counter Pressure Bottle Filler? All you need is this handy adapter! This adapter threads onto the Tapcooler and replaces the regular fitting, so that the unit can be used with these older style Perlick faucets. A must-have accessory if you have older Perlick faucets!