There is M64 Hex Lock Nut use nylon insert at the top of the nut creating tension between the nut and the threads of the mating component. It is typically a hex nut that has a built in feature that increases the nuts resistance to loosening. It is hexagonal in shape and internal thread, is cast from 304/316 stainless steel, which belongs to a kind of stainless steel threaded pipe fittings. M64 Hex Lock Nut is made for easy installation.