Complete four-piece aluminum anode kit with attaching hardware for fast and easy replacement. Produced to meet Mercury Marine original equipment manufacturer specifications to best protect your Mercruiser MR and Alpha One Drive and engine. Inspect anodes periodically for best protection and replace when seeing signs of corrosion or pitting. Don’t let corrosion damage your MerCruiser stern drive or engine. MerCruiser anodes meet or exceed mil-spec MIL-A-24779(SH) providing longer lasting protection than zinc anodes and are for us in fresh or salt water.