21X320mm Black Flat Bottom Magnesium Anode Rod for Water Heater NPT3/4 Thread Features: Magnesium rods, also known as anode rods, are mainly composed of magnesium. In the water heater liner, it and the inner liner (mainly iron) are in contact with water at the same time, forming a primary battery due to chemical principles. Since the water in the inner tank is not pure water, it always contains various impurities and has certain corrosiveness. When the water temperature exceeds 40 ° C, scale will be generated. If there is no magnesium rod, the inner tank will be corroded. With the rod,your inner liner will have longer service life since less incrustation will be generated. Simple installation and easy e,very convenient. Mainly used in water boiler, heat exchanger, evaporimeter, and boiler and so on. It has properties of softing water, de-dirt residual ,en-longing the working life of container. Specification: Material: AZ31B Magnesium Alloy  Size: 21X320mm/0.83*12.6in Thread: NPT3/4 Package List: 1*Magnesium Anode Rod