... uses seal or rubber components, for example: In electric heating pot, electric iron, microwave ovens thermostable rubberB..Electronic profession ... hardness for your option, including Buna-N (NBR), HNBR, VITON, Silicone, FluoroSilicone, EPDM, Teflon, Natural Rubber, BUTYL, SBR, Neoprene, HYPALON, ... certification and British WRAS (WRC) drinking water standard certification. Silicone Rubber O-Ring