Nylon Locknut 7/8" 14 Thread

A locknut, also known as a lock nut,  locking nut, self-locking nut, prevailing torque nut, stiff nut or elastic stop nut, is a nut that resists loosening under vibrations and torque. Elastic stop nuts and prevailing torque nuts are of the particular type where some portion of the nut deforms elastically to provide a locking action.