... Seal, Gasket, U-Ring, Quad-Ring, Glyd-Ring, Step Seal, Mechanical Seal, Extrusion Seals, Rotating Seals and wearable ... hardness for your option, including Buna-N (NBR), HNBR, VITON, Silicone, FluoroSilicone, EPDM, Teflon, Natural Rubber, BUTYL, SBR, Neoprene, HYPALON, etc ... DVGW certification and British WRAS (WRC) drinking water standard certification. Silicone Rubber O-Ring