Camco 11622 3/4" NPT x 39" Aluminum Anode Rod with Dielectric Nipple Extends the life of your water heater 3/4" NPT x 39" with dielectric nipple, installs in existing hot water connection of the tank Aluminum Anode rod corrodes so that you're water heater tank does not Attracts corrosion causing particles away from the tank protecting against galvanic corrosion