All-metal lock nuts use a deformed thread section to create prevailing torque, so they hold tension without a nylon insert. BelMetric sources hard-to-find metric sizes and styles through special order, with most shipping from our U.S. warehouse in 1-2 weeks. With no nylon to soften or degrade, they are the right choice for exhaust systems, engines, and other high-heat or high-vibration assemblies.
