Size: M3-M12. The locking type wire screw sleeve can lock the screw into the threaded hole, so that the screw is not loose when subjected to shock vibration. Because of a certain elastic, can make the load on the thread is more even, eliminate the screw and screw hole deviation between the pitch and tooth type, and can absorb vibration, thus increasing the screw thread connection strength and resistance to fatigue strength.
eBay