Details Order the optional Keg Cap™ and turn your DrinkTanks Growler into a personal keg. This growler keg tap is designed specifically for DrinkTanks growlers and will keep your beer fresh to the last drop. The Keg Cap Kit comes with a cap, CO2 injector, and two threaded 16 gram CO2 cartridges. This interchangeable cap can be used on the Classic 64 oz Growler and the Juggernaut 128 oz Growler. Your mini keg will provide you with an effortless pour everywhere, every time.