Zimar rudder zincs meet the standards set forth by Mil-Spec A-18001K, Mil-Spec A-18001A, and Mil-Spec A-18001. All Zimar rudder zinc anodes include copper contacts for permanent ground and a stainless screw. Zimar Rudder Zincs weigh more than the competition, and peform their cathodic protection job better. Most discerning boat owners choose Zimar rudder zincs to protect their vessel. Experience the Zimar Zincs advantage.