StingRay XR4 Hydrofoils designed to obtain maximum hydrodynamic performance for competition applications but also for normal level motorboats. Endowed with Tunnel-Prop technology which increases thrust while reduces friction factor at minimum. Made of hydrophilic water-absorbing material that eliminates friction. Installation with two holes on the anti-cavitation plate, fixing socket width 180 mm.↵-Save money by saving fuel↵-Get on plane in half the time↵-Keep the boat on plane with much less engine RPMs-Stabilize the boat↵-Reduce chinewalking and porpoising