The Rheem-Ruud AP18572 Powered Anode Rod (0.500" Diameter x 44" Long) is a corrosion protection component designed to extend the service life of compatible water heaters by preventing tank deterioration. Unlike traditional sacrificial anode rods, it uses a low-voltage electrical current to neutralize corrosive elements in the water, reducing tank corrosion without being consumed over ... https://www.partshnc.com/ap18572-rheem-ruud-anode-rod-0500-diax44-long