The 42 in. Eastman Flexible Aluminum/Zinc Anode Rod helps prolong the life of your water heater tank by attracting corrosion to Itself. The rod corrodes through electrolysis, a process that protects the steel walls of the water heater by attracting corrosion to a more noble metal. The anode rod is built with a carbon steel cable and 4-sections of aluminum/zinc links. It features a durable stainless steel 3/4 in. x 3 in. NPT nipple connection. Easy to install by attaching it to the top of the tank to keep it steady. The anode rod should be inspected every 2-years and replaced as needed.