Our new blue gasket is an idea we should have thought of years ago. It is so simple and easy to use. It sits on the top ledge of our recently redesigned f8b fermenters. If you own a f8 fermenter only the old g8 gasket will work on that model. The ledge on the new model is one half inch wide and is the top rim of the tank. The blue gasket sits in the grove on this ledge and the lid pushes down over to seal.The new gasket is blue and is very easy to use.