Extend the life of your cask ale with this Cask Breather. It attaches to your CO2 regulator (set at about 5 PSI) with a pressure hose to replace head space with CO2 at atmospheric pressure, which acts as a blanket to protect the ale from exposure to oxygen. If your cask is being dispensed horizontally, a cask breather spigot will be required. This spigot is not necessary if the cask is being dispensed vertically. This cask breather can be used for multiple casks.