Nylon insert lock nuts are designed to be used where you don't want the possibility of the fastener becoming loose due to vibration, shrinkage or application.
A nylock locking nut is a fastener that incorporates a nylon component to effectively lock the nut into position on the bolt. The nylon component of the nylock nut has a smaller inside diameter than the actual nut, thereby acting to lock the nut in place by squeezing the nylon firmly around the bolt when tightened.

Made from Stainless Steel.
Nylon insert lock nuts are the choice for most marine, industrial, construction and OEM applications where corrosion resistance is a primary factor.

Pack of 20 M6 nylon insert locking nuts