120S and MS25S Saildrive Aluminium ring anode.
Please note this is an Aluminium anode for brackish water use. A Magnesium version should be used for freshwater, Part number 876604. For saltwater, Volvo Penta Part Number 876286 should be ordered. Anodes should not be mixed on any installation.
If your anode is worn away by 33% or more, it is advisable to change it as more of its surface area has been worn away and the remaining anode will wear away much quicker.
The anode protects the drive, engine and propeller from corrosion due to electrical currents in the water. When you change your anode, make sure that it is not painted and that it has good contact via the bolts and metal surface to the Saildrive.
Volvo Penta Part No: 876286A