Screw Plug Immersion Heater, 18,000 W Watts, Sheath Material Copper, Screw Plug Material Brass, Watt Density 44.13 W/sq in, Heater Voltage 480V AC, 3 Phase, Overall Length 51 3/4 in, 2 1/2 in NPT, Enclosure Type NEMA 1, Min. Immersion Depth 47 3/8 in, Special Information Corrosion- Electrical Wiring Hardware, Recompacted Element Bends Restore Insulation Resistance After Forming, Silicone Resin Element Seal Standard, For Use With Clean Water, Non-Corrosive Material, Includes Screw Plug