The Whale Tail XL aluminum stabilizer and ski boat fin improves performance in any I/O or outboard motor boat. The fin￢ﾀﾙs unique hydrodynamic design extends behind the prop to utilize prop wash energy which is normally lost. Whale Tail transforms this energy into lift for immediate response when the throttle is applied. Use the Whale Tail XL in freshwater or salt-water to improve performance of any boat. Other benefits include fuel savings and increased top end speed. The 15-minute installation is simple and straight forward. Made of sturdy, marine-grade clear anodized aluminum plate. Stainless steel mounting hardware is included.