The McCormick 6513688M91 Valve is a genuine OEM replacement part designed for various McCormick X-series tractors including X4.20, X4.30, X4.40, X4.50, X4.60, 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, X7.690, X8.660, X8.670, X8.680. It also fits a wide range of Massey Ferguson tractors. This essential valve ensures proper system functionality and maintains optimal performance for compatible agricultural machinery. Replaces multiple OEM part numbers.