A Nyloc nut, also referred to as a nylon-insert lock nut, polymer-insert lock nut, or elastic stop nut, is a kind of lock nut with a nylon collar that increases friction on the screw thread. The nylon collar insert is placed at the end of the nut, with an inner diameter (ID) slightly smaller than the major diameter of the screw. The screw thread does not cut into the nylon insert, instead, the insert deforms elastically over the threads as tightening pressure is applied. The nylon insert locks the nut against the screw as a result of friction, caused by the radial compressive force resulting from the deformation of the nylon. Take note that this product, being part nylon, is heat and chemical sensitive. Where these elements apply, please check this nut is suitable for your job. Alternatives are Conelock nuts and Lock nuts, which are located in the BOLTS ONLINE Nuts Category.