Dernord 24V 600W Heating Element Submersible Water Heater Element Stainless Steel Immersion Heater with 1 Inch NPT Fitting 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 Easy to install for heater parts,Stainless steel surface has electropolish UL and cUL listed to the safety standards Supplied with silicon sealing washer which is flexible and waterproof