The McCormick 3657701M91 is an authentic OEM spring designed for a wide range of McCormick tractor models. This crucial component is compatible with X4.20, X4.30, X4.40, X4.50, X5.20, X5.30, X5.40, X5.50, X6.420, X6.430, X6.440, X7.440, X7.450, X7.460, X7.650, X7.660, X7.670, X7.680, X8.660, X8.670, and X8.680 series tractors. Utilizing genuine McCormick parts like the 3657701M91 ensures the longevity and reliable operation of your agricultural machinery.