The McCormick 300440A1 is a genuine OEM replacement knob designed for various McCormick X-series tractors, including X4.20, X4.30, X4.40, X4.50, X4.60, X4.70, X4.80, X4.90, 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, X8.680, X8.690, and X8.690 VT-DRIVE models. This versatile knob also provides fitment for a wide range of Landini tractor models, such as the 4-series, 5-series, 6-series, 7-series, and 8-series, ensuring proper function and a secure fit. Essential for maintaining the original equipment functionality and aesthetic of your agricultural machinery.