Stainless Steel M3mm HEX Nylon Insert Self Locking Security Nut
hex nut with a nylon filled collar at its back end. When a screw or
bolt reaches the collar, the threads and nylon form a tight frictional
fit, restricting movement between the nut and bolt or screw when
subjected to vibration.
What you Get:
1 x HEX Stainless Steel Secure Nut