Loctite 243 primerless, oil tolerant, medium strength, removable blue threadlocker is an oil tolerant, removable, medium strength, blue threadlocker designed for the locking and sealing of threaded fasteners between 1/4 Inch and 3/4 Inch (6 to 20 mm). It not only works on active metals (e.g. brass, copper) but also on passive substrates such as stainless steel and plated surfaces. It tolerates minor surface contaminations from various oils, such as cutting, lubrication, anti-corrosion and protection fluids. - Loctite 243 is designed for the locking and sealing of threaded fasteners which require normal disassembly with standard hand tools. The product cures when confined in the absence of air between close fitting metal surfaces and prevents loosening and leakage from shock and vibration. The thixotropic nature of Loctite 243 reduces the migration of liquid product after application to the substrate.