An anode rod protects your water heater from corrosion by attracting corrosive elements in water, so they attack the anode rod rather than the interior of your water heater’s tank. Simply remove the plastic drain plug and insert the unit. Atwood’s anode rod is 4.5″ long with a 1/2″ pipe thread and available in Magnesium alloy, while the Suburban anode rod model is 9″ long with a 3/4″ pipe thread, available in Aluminum or Magnesium. When replacement is necessary, unscrew the old one and insert the new one. These are easily replaced and should be checked every six months.