The single most important factor in tank life is the condition of its anode. Aqua Pro Magnesium Anode Rods will attract the elements that cause corrosion, protecting the tank from those elements. Simply replace your MPT drain plug with the Aqua Pro Anode Rod to protect your tank. Magnesium Anode Rod for Suburban and Morflo Water Heaters.• Compatibility: Atwood Water Heaters• Diameter: 0.620 Inch• Length: 4-1/2 Inch• Thread Size: 1/2 Inch-14• Material: Magnesium• With Drain: Yes• Quantity: Single Significantly Extends The Water Heater Tank Life Magnesium Anode Rods Will Attract The Elements That Cause Corrosion, Protecting The Tank From Those Elements Out Of Box Coverage | Aqua Pro Water Heater Anode Rod, For Atwood Water Heaters