Zinc For SM201180 Side-Power Bow Thruster Zinc Anode SE120, SE150, SH160, SE130, SE170 Zinc For SM201180 Side-Power Bow Thruster Zinc Anode SE120, SE150, SH160, SE130, SE170 Diameter: 1-7/8" Height: 1-5/8" Weight: 0.25 lbs Fits models SE120, SE150, SH160, SE130, SE170, SE210, HYD220, SP200TC-32V, SP240TC, SP285TC, HYD300, SP125T, SP155TC. Two (2) anodes required. Zinc Is For Saltwater Use