Boiler Gaskets are an incredibly important part of your boiler and should be made with the highest quality materials. Topog-E Series 180 gaskets rise to the extreme demands of the steam boiler market. Made of a special proprietary rubber, these gaskets are designed to be used at operating pressures of up to 180 PSI and upwards of 380°F in saturated steam temperatures. This 3" x 4" x 1/2" gasket will replace easily and fit perfectly. Prevent leakage around your hand hole with Topog-E Series 180 Gaskets.