Duravit 1002970000 Flush Valve Gasket for Geberit HET, "Flapper" inside measurement = 32mm, outside measurement = 85mm (could be clear or black) for top flush button configuration Duravit toilets, 1930 Series 2pc 213001, 087230, Darling New 1pc 212301 and 2pc 212601, 09312, Happy D 2pc 011201, Starck 2 1pc 016301, and 213301, and Vero 1pc 210301