The McCormick E42052 is a genuine OEM piston ring designed for McCormick D-Series tractors, including models D-430, D-439, D-440, and D-450. This precision-engineered ring, with a bore diameter of 95.00 mm and a thickness of 3.00 mm, is crucial for maintaining proper engine compression and efficiency. It is an essential component for engine overhaul and maintenance, ensuring reliable operation and longevity for your agricultural machinery.