The McCormick 6666922A1 Mass Kit is an original equipment manufacturer (OEM) part designed to provide additional ballast for McCormick X4, X5, X6, X7, and X8 series tractors. This genuine mass kit ensures proper weight distribution and enhanced stability, crucial for various agricultural and heavy-duty applications. It is specifically compatible with models 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, X5.60, X5.70, X5.80, X5.90, X6.40, X6.45, X6.50, X6.55, X7.440, X7.460, X7.650, X7.660, X7.670, X7.680, X8.660, X8.670, and X8.680.