The Doel-fin Hydrofoil Stabilizer is designed to allow water to flow over the fins to create lift that compensates for stern weight. It improves rough-water handling, saves you 10%-50% on fuel costs, eliminates cavitation and improves prop efficiency. With the boat planing out easier, the motor doesn't have to work as hard. The Doel-fin Hydrofoil Stabilizer fits all outboards and out-drives, and installs in less than 15 minutes. Mfrs. limited lifetime warranty.