The Suburban Anode Rod Replacement protects your water heater tank from corrosion by attracting corrosive elements in water so they attack the sacrificial anode rod rather than your water heater tank interior. Simply remove the anode rod from the tank and inspect it every three months. If it is mostly eaten away, replace it with a new one to extend the life of the tank. 0.75" dia. x 9-1/2"L | Suburban Anode Rod Replacement Magnesium