Missing the pressure relief valve assembly on your Fermenator? We've got your replacement right here! This is a full Fermenator pressure relief valve assembly which includes the o-ring. The Fermenator pressure relief valve fits into the removable lid hatch on your Fermenator and can help relieve pressure if it builds to excessive levels. The weight of the pressure relief valve should limit the pressure to 3 PSI and will prevent a dangerous buildup of pressure if it should grow beyond this. A must-have for your Blichmann Fermenator!