Anode Propeller Boss
Propeller boss anodes to be threaded. These are a solid bulb of zinc, shaped aerodynamically to suit the end of your propeller shaft.
They require threading on the flat end to suit your propeller shaft thread.
They are 99.99% pure zinc, so pass US Coast Guard standards for electrolysis protection against corrosion.
2 sizes: 56mm and 74mm maximum diameter 18009,18010