Rheem SP11309C R-Tech Resistor Magnesium Anode Rod with 44-Inch Length and 0.7-Inch Diameter For best results, use only Rheem replacement parts for repairing your Rheem Water Heater Anodic Material: Magnesium, Total Length (in.): 44-3/8, Rod Diameter (in.): 0.700, Hex Head Size (in.): 1-1/16 Thread Size - NPT (in.): 3/4, Resistored: Yes Kits which contain this part: 45W363