Tractor-Trailer Air Brake Lock This cast aluminum lock completely encases cab brake knobs Protects idling and parked tractors Rotating Disk Cylinder Core; This is not your typical lock. Lost keys can be replaced, if registered with manufacturer. Number listed on key tag needed. Not compatible with Freightliner T600 (2015, 2016), Freightliner Cascadia (2016), International Pro Star (2016)