The insert is mechanically joined to the nut body and securely locks the bolt, while the nut secures the joint. The locknuts serve in rail, off-road, construction, mining, machinery, and amusement-ride applications where periodic maintenance requires reusability. The fasteners provide vibrationproof fastening in applications where double nuts, serrated fasteners, distorted and nylon insert locknuts fail. Installation requires a standard torque wrench or ratchet. The locknuts withstand temperatures to 750F and come in standard 3/8 to 4-in. sizes that are compatible with Grade 5 or 8 bolts. Metric sizes are available.