ENGINE REBUILD KIT COMPATIBLE WITH OPPOSED TWIN CYLINDER BRIGGS & STRATTON 16hp-18hp, COMES WITH A COMPLETE GASKET SET WITH CRANKSHAFT SEALS, FOR VERTICAL OR HORIZONTAL OPPOSED BRIGGS AND STRATTON ENGINES.TWIN OPPOSED CYLINDER MODELS THAT START WITH EITHER 40 OR 42 in the model number, 400400, 400700, 401400, 401700, 402700, 404700, 402400 & 422700 STANDARD PISTONS WITH CHROME 3 PIECE OIL RING FOR BETTER OIL CONTROL, Note: This overhaul rebuild kit will fit Briggs & Stratton opposed engines only, WILL NOT FIT INTEK or VANGUARD engines WHICH ARE OVERHEAD VALVE!!!