Rheem SP10869PH Screw-In 240-volt by 5500-watt Element, Premium Resistored Stainless Steel Element - 240V/5500W stainless steel resistored mwd - 1 in screw-in Watt density classification: mwd, input Voltage (V): 208, input Voltage (V): 240, wattage at 208V (w): 4130 Element diameter (in.): .316, element length - flange to tip (in.): 13.47, mounting Type: threaded, ACTUAL thread size - outside diameter.): 1-9/32 Thread Type series designation: NPSM, configuration: fold back, nominal thread size - (in.): 1, threads per inch: 11-1/2