Materials: 316L Stainless Steel Plates Copper Braze (99.9% Copper) Connections: 1-1/4" MNPT Applications: BT Series heat exchangers designed especially for hydronic heating and cooling applications, including radiant heating, ice and snow melt applications, domestic hot water heating (DHW), outdoor wood stove / boiler / furnace heating, hydraulic oil cooling, and as a general alternative to shell & tube heat exchangers.