Loctite 243 Primer less Threadlocker is an oil-tolerant, removable, medium-strength, blue threadlocker designed for the locking and sealing of threaded fasteners between 1/4" and 3/4". It not only works on active metals, 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.