Triple Stainless steel Deep Tank Heaters:Watt densities of 35 watts per square inch (5.4 w/cm2) ensure long service life. Stainless steel Immrsion Heaters0.5 to 54 kW, 35 watts/square inch (5.4 watts/square centimeter) nominal (other sizes and watt densities available). 120, 240, 480 volts standard, 208, 380, 415 and other voltages available. Choice of steel, stainless steel (304 and 316) and ...