This is a genuine Zetor 53129901 gasket-sealing ring, also known as an oil seal or 'joint spi', with precise dimensions of 50mm inner diameter, 80mm outer diameter, and 13mm thickness. It is specifically designed for various Zetor tractor models, ensuring optimal performance and preventing leaks. Compatible series include the Zetor 3320, 3340, 4320, 4340, 5320, 5340, 6320, 6340, 7320, 7340, and the Proxima series, providing a reliable and exact fit for maintaining machinery integrity.