Durable Stainless Steel Construction;Polyurethane Resin Foam with R12 Insulation Valve;Offered in 13, 26, 40, and 80 Gallon Capacities;White Outer Housing;1/2" NPT Aquastat Port;Standard 6KW (2 each 3kw Heater Elements for BT26-H, BT40-H and BT80-H. Only one 3kW heater element for BT13-H) Electric Heat 240VAC 1PH/60Hz