Breather valve that extends the life of a cask by utilizing a CO2 gas connection and a one-way-valve.
When using this with an ale extractor, simply connect a CO2 line to one end of the aspirating valve, and a line leading to the venting outlet of the ale extractor. Set your line pressure to 5-10 PSI.
If using this aspirating valve with a gravity dispensing setup, you will also need the CO2 barrel spigot found at this link (CLICK HERE!), and use that instead of a wooden spile or cask ventilator.