Godfrey Premium Collar Zinc 2 3/4” – Marine Shaft Anode for Corrosion ProtectionGodfrey Premium Collar Zinc 2 3 4 is a marine shaft anode designed to protect propeller shafts and underwater metal components from galvanic corrosion. This collar zinc installs directly onto the shaft and reliably protects against corrosive electrolytic currents in saltwater environments. Zinc sacrificial anodes work by sacrificing their own material to prevent corrosion of more valuable metal parts such as the propeller, shaft, and nearby hardware.