Blackzon 4mm Silver Steel Flanged Nyloc Nuts 4Pcs

Nyloc Nuts are lock nuts with a nylon collar that increases friction on the screw shaft. The collar has a slightly smaller inner-diameter than the thread size. The screw does not cut into the nylon insert, rather, the insert deforms to the threads of the screw. The insert locks the nut against the screw as a result of friction, increasing strength and reliability.