Mill certified Grade 5 SAE J429 hardened steel shear bolts. Nyloc nut prevents loosening from vibration. Kit includes 5 shear bolts and 5 nylon locknuts. Universal Size for Rotary Cutters: 1/2" Diameter, 3-1/2" Length. Compatible with most rotary cutters such as Bush Hog and King Cutter. Zinc (Cr+3) RoHS compliant finish prevents corrosion. Fits most Rotary Cutters such as Big Bee, Bush Hog, Ford, Hico, Howse, John Deere, Servis, Servis Rhino, Sidewinder, Modern, Mohawk, Kodiak, Woods, Terrain King, King Kutter, Agri Series Cutters. Kit includes 5 replacement shear bolts and 5 nyloc nylon insert lock nuts.