Permatex Medium Strength Threadlocker, Blue: Service Removable; Locks Threaded Fasteners Against Vibration Loosening; Uses - Valve Cover, Water Pump, And Oil Pan Bolts; Ideal For Fasteners 1/4" To 3/4" (6 To 20 Mm) In Size. Permatex, Made For The Professional. Made In U.S.A. Oem Specified. Locks Threaded Fasteners Against Vibration Loosening.