LOCTITE? 243 Medium Strength Threadlocker 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, prevents loosening and stop leakage from shock and vibration. LOCTITE? 243 Medium Strength Threadlocker provides robust curing performance. It not only works on active metals (e.g. brass, copper) but also on passive substrates such as stainless steel and plated surfaces.