Rudder Anode Zinc 1 7/8 in. | Martyr CMR01 Martyr Rudder Anode Zinc 1 7/8 in. | CMR01 Martyr CMR01 provides corrosion protection for boat rudders or trim tabs in salt water. Constructed from traditional zinc, this anode defends against electrolysis-induced corrosion, ensuring your vessel is properly protected. Rudder and trim tab anode Designed to mount to rudders and trim tabs to protect from the corrosive effects of stray current 1 7/8 in. diameter Sold as 2 halves held together with a stainless steel bolt and nut Each half is 1/4 in. thick Zinc anode is for use in salt water Martyr anodes are made of a high purity specialized alloy based on the US Mil Spec