This cask ventilator (Autovent) can be used either in vertical or laydown dispense.
It replaces both the soft and hard pegs and is made from a high impact resistant food grade material.
Iit contains a (duck bill) non return valve which controls the amount of air entering the cask, the only way air can enter the cask is by dispensing beer.
Because it has an air tight seal it can add a couple of days onto the longevity of the beer.