Dernord 24V 900W Stainless Steel Heating Element Submersible Water Heater Element 24v DC heater connects with batteries, solar panels, hydroelectric generators and wind turbine dump 1" NPT flange fits USA standard water tank or your own custom heater tank UL and cUL listed to the safety standards Stainless steel surface has electropolish Supplied with silicon sealing washer which is flexible and waterproof