Park Tool TLR-1 Medium-Strength Threadlocker - Blue. Features: Threadlockers lock threaded assemblies and keep them from loosening over usage. Formulas are oil tolerant and both compatible with steel, aluminum, and carbon fiber but are not recommended for titanium fasteners TLR-1 is blue medium strength TLR-2 is red high strength 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