This genuine McCormick 3661328M91 knob is an essential OEM replacement part designed for various McCormick X4, X5, X6, and X7 series tractors. It also serves as a direct fit for Massey Ferguson MF 5400, MF 6400, MF 7400, and MF 8400 series agricultural machinery, ensuring reliable operation and proper control. Manufactured to original equipment specifications, this knob provides durability and precise fitment for critical machine functions.