Sealing ring - TOOGOO(R) 125x Rubber Grommet Car Firewall Hole Plug Assortment Electrical Wire Gasket Kit 18 different sizes, 125 pieces. The sealing ring is made ??of superior rubber. Variety of thickness and size are all in one box, very convenient to use. Heat-resisting, mineral oil-resisting, wear-resisting. Suitable for pipes, hydraulic, air, gas, and many other industrial applications.