This listing is for a set of four (4) H896CP STD or 4.00" Bore Diameter Sealed Power hypereutectic Dish top pistons and a cast piston ring set compatible with Mercruiser 3.0LX 140hp applications using the Chevrolet 181cid 3.0L 4-cylinder engine. These are the earlier model dish top pistons, Some later model engines require a flat top pistons.