These new Top End Kits contain all the necessary components to install a new piston, or cylinder in the 2017-2018 KTM and Husqvarna 250 and 300 2-stroke models. They feature FKM (viton) Cylinder head O-rings, AFM(Aluminum Foam Material) and Rubber Coated Steel cylinder base gaskets in all stock replacement thicknesses. Included in the kit are AFM Power Valve Gaskets, Control Valve O-rings, Exhaust O-rings, and Head Crush Washers.