These little Martyr zinc anodes are often used on outboards and are a universal fit. Once installed, check for continuity to ground using an ohmmeter. A stainless star washer between the anode and wherever you mount it will help insure continuity.
How much salt water use do you expect the motor to see? If it’s just occasional use, it probably isn’t neccesary as long as the motor is flushed well after. For a motor or kicker mounted on a boat which lives on the ocean, then yes.
