Nylok screws, Nylok is a self-locking element comprised of nylon permanently embedded into the threads of a fastener. The pellet is a drilled hole with a plug of over sized nylon wedged into the hole. The strip is a milled slot with a string of over sized nylon wedged into the slot. When the pellet & strip are engaged it creates a wedge between the fastener and mating part compressing the nylon and creating metal to metal contact opposite the element. This metal to metal contact results in a positive resistance to vibration and loosening. Since nylon has great memory characteristics, this locking element can be reused several times.