Replacement Only Diecast to highest Mil-Spec standards Protection in salt water Easy installation Made in USA This Zinc Hull Boat Anode provides cathodic protection against corrosion for marine vessels in brackish and salt water. Die-Cast to Highest Mil-Spec Standards and made in the USA this Hull Anode manufactured by Sea Shield Marine is designed by divers for divers. Conforms to Mil-SPC MIL-A-18001 Standards providing the worlds finest protection.