WMF Perfect Replacement Part Seal Ring for Residual Pressure Safety, for Pressure Cookers 2.5 l - 8.5 l, 18 cm and 22 cm. Replacement Part: The seal for the residual pressure safety for the main valve is suitable for all WMF pressure cooker lids of the Perfect series with a diameter of 18 + 22 cm (2.5 l, 3.0 l, 4.5 l, 6.5 l, 8.5 l). It is the classic among pressure cookers: the WMF Perfect. For many years, it has confidently maintained its place in the WMF range - and for good reason. Its classic design is timeless, and its functionality is always adapted to current technology. Like all other pressure cookers from WMF, it is made of Cromargan, making it rust-free, easy to care for, and indestructible. Its large cooking signal allows for easy operation, its internal measurement markings enable precise filling, and the removable handle makes cleaning easy. Not only that: thanks to its Trans Therm All-Hob Base, the WMF Perfect Steamer is suitable for all types of stoves, including induction. The WMF Perfect series offers pressure cookers in five different sizes and as a two-piece set.