Camco’s Aluminum Anode Rod is a sacrificial rod that extends the life of your water heater tank by drawing the corrosion process to itself (rather than the tank lining of the water heater). As a result, the water corrodes the rod rather than your steel tank. The 5/8-inch OD aluminum anode rod measures 42-inches long and has ¾-inch – 14 NPT threads. It is constructed of aluminum.