Significantly Improves Performance! The Sting Ray Hydrofoil eliminates cavitation, prop blow out, bow rise, porpoising, and bouncing. A new Speed-XP hydrophilic material creates a water-on-water surface eliminating drag and making Sting Ray the fastest hydrofoil available. Speed covers reduce drag by preventing water "slap" against the hole. Fits any I/O or outboard with a cavitation plate. Torque equalizers (#28986) neutralize steering torque for better control and tracking at all speeds. The Classic Junior Hydrofoil is recommended for 9.9 - 40 hp engines.