The Whale Tail XL features a unique hydrodynamic and stabilizing design that extends behind the prop to utilize prop wash energy which is normally lost. Whale Tail XL transforms this energy into lift for immediate response when the throttle is applied. Use Whale Tail in fresh or saltwater to get skiers up in less time, flatten wake for skiing, stabilize bow-light boats, smooth out ride in rough conditions, and increase top speed. Mounts on the anti-cavitation plate of all I/Os and outboards. Installs in just minutes. Marine-grade aluminum construction with durable anodized finish. Stainless steel hardware included.