Extends out behind the prop to utilize the prop wash energy that is normally lost breaking the water. This energy is transformed to lift against the Whale Tail XL for immediate response when the throttle is applied. Mounts on the anti-cavitation plate of all I/O's and outboards. Made of marine grade aluminum with durable anodized finish. Stabilizes bow light boats. Pops up skiers in less time. Increases top speed and saves fuel in most applications. Reduces porpoising and cavitating.