The McCormick 6645841A1 DUCT is an original equipment manufacturer (OEM) part designed for various McCormick X4 series tractors. This genuine duct ensures optimal airflow and maintains the integrity of the tractor's internal systems, providing a precise fit and reliable performance for models including X4.20, X4.30, X4.40, X4.50, X4.60, X4.70, X4.35, X4.45, X4.55, X4.65, X4.70M, X4.80M, X4.35M, X4.45M, X4.55M, X4.060, X4.070, X4.080, X4.090, X4.100, X4.110, X4.060M, X4.070M, X4.080M, X4.090M, X4.100M, and X4.110M.