These are metric replacement zinc anodes for Beneteau propeller shaft nuts.
Cast-in stainless steel mounting insert provides better grounding and prevents the anode from loosening, even as it is being consumed.
Propeller nut anodes can significantly increase the life of the propeller and the connected shaft.

• All Sea Shield zinc anodes conform to Mil Spec MIL-A-18001 for maximum protection.
• Less than half the weight of comparable zinc anodes
• Made in California, USA