Permatex Red Large Diameter Threadlocker is OEM specified. A high strength threadlocker for heavy-duty applications. This threadlocker is the preferred choice for locking large bolts and studs 1" and larger (25mm+). Locks and seals while preventing parts from loosening due to shock and severe vibration. Protects threads from corrosion. Localized heating and hand tools are required to separate parts. Conforms to ASTM D5363 AN0211, Mil-Spec 46163A, Type I, Grade L.