Threadlockers lock threaded assemblies and keeps them from loosening Park Tool TR-1 Threadlocker  Medium Strength Threadlocker (Competes with Loctite® 242/243) Compatible with steel, aluminum and carbon fiber Oil tolerant Not recommended for titanium fasteners Notice: Park Tool AP-1 Adhesive Primer must be used to prep all components, fasteners and carbon fiber surfaces prior to application of Park Tool threadlockers or retaining compound. Failure to do so could result in permanently bonded parts 10 ml bottle