The forgefix nyloc hexagonal nuts incorporates a nylon component to effectively lock the nut into position on the bolt the nylon component has a smaller inside diameter than the actual nut this locks the nut in place by squeezing the nylon firmly around the bolt when tightened unlike a standard locking washer the nyloc nut prevents the nut from loosening under vibration as the nylon is tightly wedged into the bolt threads and provides resistance to turning when tightened the nuts are zinc plated