Presto 09908 Pressure Cooker / Canner Gasket; Sealing Ring & Auto Air Vent Pack Presto 09908 Pressure Cooker / Canner Sealing Ring With Auto Air Vent The Sealing Ring Fits Around The Inside Rim Of The Cover And Forms A Pressure-Tight Seal Between The Cover And The Body Of The Pressure Canner During Canning And Cooking. Fits Models: 603 50 60 603 604