The Amtrol 2500-218 Flange Gasket is a replacement sealing component designed for compatible WH7 and WH9 Series BoilerMate tanks. It fits between the tank flange and connected components to create a secure, leak-resistant seal during operation. Replacing older gasket part numbers 2704-403 and 392932, this gasket is used in hydronic heating and domestic hot water systems equipped with ... https://www.partshnc.com/2500-218-amtrol-flange-gasket-for-wh79-series-boilermate-tanks-replaces-2704-403-392932