Standard Size Fin: 8.9 - 100 HP, Boats Up to 17' Guaranteed improvement in overall performance and handling For boats 17 feet and smaller, and outboards 8.9hp - 100hp (for stock brackets) Get on plane faster Plane at lower speeds and RPM settings Improves performance, fuel economy and overall handling Shields the propeller from damage due to underwater impacts Reduces costly repairs to the propeller and lower unit gearing Absorbs impacts Controls cavitation and porpoising Fits on outboards and inboard/outboards Simple Installation Made from an energy absorbing compounded glass filled thermoplastic