Zinc shaft collar anode to suit most propeller shafts. For use in Salt water only.Shaft collar anodes are an ideal solution for boats with limited clearance between the propeller and bracket or stern gear. The ZSC and ZSC(T) range excel for this purpose when space is limited.The ZSC(T) collar is one of the thinnest shaft anodes on the market, allowing boat owners with minimal shaft clearance to protect their valuable propeller and shaft. It is important to maintain some gap to allow for engine movement.