Accurately drill holes in fasteners allowing them to be mechanically locked in place with safety wire. Fixture accommodates most 3/16", 1/4", 5/16", 3/8", 7/16", 1/2" and 5/8" socket head and hex head fasteners. Guide bolt tightens against fastener, holding it secure for drilling. Fixture includes two guide bolts and two 1/16" drill bits conveniently stored within the fixture.