Replacement cylinder head gasket for the 79cc HF engine. Use as a high compression gasket for the 99cc Predator. The stock 99cc cylinder head gasket is .040" thick this gasket is .010" thick which will increase compression. When used on the 99cc Predator check piston pop up first. If the piston is out of the hole more than the thickness of this gasket, the piston will make contact with the cylinder head...not good. The piston height varies in these engines so it would be wise to check your piston depth before installing this gasket.