This is a genuine Zetor part number 78350946, an M16x1.5 nut with a height of 13mm and a 24mm wrench size. It is an essential component for a wide range of Zetor tractor models, ensuring secure fastening and reliable performance. This OEM Zetor nut is compatible with models including 3320, 3321, 3340, 3341, 4320, 4321, 4340, 4341, 5320, 5321, 5340, 5341, 6320, 6321, 6340, 6341, 7320, 7321, 7340, 7341, 8621, 8641, 9621, 9641, 10641, 11441, 11741, 12441, 12841, 1340, 1341, 13841, 14841, 15841, 16841, 17841, and 18341.