Nylon Insert Lock nuts have a nylon ring that when tightened on a bolt, resists loosening under all types of vibrations and torque. JM Hardware nylon insert locknuts are available in a variety of sizes and materials including low and medium carbon, heat treatable steel grades, including non-ferrous materials.If you are looking for a threaded fastener that will resist loosening, then nylon insert locknuts are the best solution for your project. Used for industrial purposes or in the Aerospace industry, this fastener is reliable and durable.