Fits all 40hp, 1300, and 1600cc type one engine cases that require grooved cam plugs. Posi-Seal Cam Plugs are manufactured by an OEM supplier with a stiff inner steel core and coated with heavy hi-temp rubber. Posi-Seal Cam Plugs fit perfectly, they are reusable, and they never leak. The difference is in the rubber seal that goes around the cam plug.