Abstract: A locking system including a combination of a multi-strand locking wire and a ferrule having a thin walled crimpable section useful for preventing threaded fasteners from loosening due to vibration, each of the fasteners having an aperture for receiving the locking wire. The ferrule has a larger stop end for interfering with the fastener aperture and a smaller thin walled barrel end for crimping. In one configuration the ferrule is a thin walled cylinder with one end flared out to form the stop end for facilitating insertion of the locking wire. The thin wall of the barrel end allows reduced crimping force. Further reduction of crimping force is achieved by crimping the ferrule to deform only small localized areas on the barrel end. The ferrule may bear identification marks which may be either pre-marked or applied during the installation such as by crimping.