Camco RV Magnesium Anode Rod extends the life of a water heater by attracting corrosive elements in the water, protecting the tank and elements from corrosion. This Anode Rod fits Atwood water heaters. Patented. Extends the life of a water heater by corroding itself so that the water heater doesn't Magnesium anode rod 0.5" diameter x 4.5" long Provides protection against galvanic corrosion 1/2" NPT fits Atwood heaters