The Sting Ray XRIII is designed with a new sleeker hydrodynamic profile for the fastest hole taking yet. This unique design reflects offshore supership tunnel technology. By capturing prop wash, the XRIII harnesses its power to increase thrust. You'll enjoy better performance and better fuel economy. The XRIII also uses a 3-point locking system for easy no-drill installation. No more measurements. No more templates. No more damage to your engine. For engines up to 300 HP.