The McCormick 366141X1 is a genuine OEM piston ring designed for International Harvester and McCormick B-Series and 400-Series tractors. This critical engine component ensures proper cylinder sealing, maintaining compression and preventing oil consumption. With an outer diameter of 79.37 mm and a thickness of 2.36 mm, it is engineered for precise fitment and reliable operation in models such as the B-250, B-275, B-414, 434, and 444.