The McCormick 3666659M91 is an authentic OEM shim designed for critical spacing and alignment applications within various McCormick agricultural machinery models. This precision-engineered shim, with a thickness of 0.51 mm, an outer diameter of 38.1 mm, and an inner diameter of 25.4 mm, ensures optimal component clearances, reduces wear, and contributes to the longevity and efficient operation of your equipment. Weighing approximately 0.01 kg, it is a vital component for maintaining proper mechanical function in compatible McCormick tractors.