Thread Lock by Loctite. Details:Dual cure, acrylic dimethacrylate ester fluorescent threadlocker designed for the permanent locking and sealing of threaded fasteners. LOCTITE 263 is a red, dual cure, acrylic dimethacrylate ester fluorescent threadlocker designed for the permanent locking and sealing of threaded fasteners. It cures between close fitting metal surfaces and prevents loosening and leakage from shock and vibration. It works on active metals (e.g. brass, copper) and passive substrates such as stainless steel and plated surfaces. LOCTITE automotive aftermarket products are not just OEM-specified, they are also designed by auto manufacturers and lab tested. Engines of nearly every professional race car are assembled and maintained with LOCTITE brand adhesives, sealants, gasket makers, and coatings. Whether gasoline or diesel, from bolts and gaskets to cooling lines and core plugs, Henkel products are used to seal, secure, and repair vehicle components.