The McCormick 3685371M1 is a genuine OEM piston ring designed for optimal engine performance and durability in various McCormick and Massey Ferguson agricultural machinery. This essential engine component ensures proper compression and oil control within the cylinder. It is compatible with McCormick CX, MC, MTX, XTX, and ZTX series tractors, as well as numerous Massey Ferguson 5400, 6400, 7400, and 8400 series models, providing reliable fitment and maintaining engine efficiency.