Sacrificial anode rod protects your water heater tank from corrosion by attracting corrosive elements in water, so they attack the 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. - See more at: http://m.campingworld.com/shopping/item/suburban-anode-rod-replacement/42180#sthash.yTCbiUWk.dpuf