The McCormick 6633810A1 is a genuine OEM fuel tank cap designed for a wide range of McCormick agricultural tractors. This cap comes equipped with a key for secure locking, preventing fuel theft and contamination. It ensures a tight seal, maintaining fuel system integrity across various McCormick series including C, CX, MC, MTX, T, X10, X4, X5, X6, X7, XTX, and ZTX models. This essential component is crucial for the proper operation and security of your tractor's fuel system.