JE Pistons Ring Sets 1.2-1.5-4mm 3.839JE Piston Rings are designed to maximize horsepower through precision sealing of combustion pressure. They are offered in a huge selection of sizes, various materials, and in multiple thicknesses to suit a wide variety of engines. JE Pistons also offers an array of custom piston ring services including back cutting, dyke cutting, lapping, grinding, and PVD coating. These services, the same used by top NHRA Pro Stock and NASCAR teams, are now available