The River Runner protects your prop and skeg in shallow waters with the unique gravel deflector and bottom plate. Water dynamic for high performance boats. Parts include pressure plate, skeg protector, gravel deflector with slots, bottom plate protector and shock absorber, and back up protector. Made of 304 stainless steel.a Size Aa 9.9 - 30 hpa Honda 9.9 - 50 hp Bottom plate protector absorbs shock 304 stainless steel Fits 9.9 HP to 30 HP / Honda 9.9 to 50 HP River Runner, Size A.