The lock bump set is used to gain entry to a facility by repetitively hammering a bump key into the key way of a target lock. The bump keys are cut to apply pressure to all pins when inserted. A rebound ring (black) is placed on the key to allow it to move back and forth in the key way when struck with the hammer. Light turning force is applied to the key to allow the pins to retract and bind when struck with the hammer. Once all pins match the applied bitting in the lock, the key will turn freely.
Instructional videos describing use of the tool are listed below.
Lock Picking Lawyer instructional video: https://www.youtube.com/watch?v=r3cuVPSySZw