Nyloc Nut

A nyloc nut, also referred to as a nylon insert lock nut, polymer insert lock nut, or elastic stop nut, is a kind of locknut. It is a nutwith a nylon collar insert that resists turning. The plastic insert is placed at the end of the nut and its inner diameter (ID) is slightly smaller than the major diameter of the screw. The insert deforms elastically over the threads of the screw, but threads are not cut into the nylon. The nylon insert locks the nut by applying a compressive force against the screw. Nyloc nuts retain their locking ability up to 250 °F (121 °C)