LOCTITE® 243™ Primerless 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" (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 the recommendedreplacement for Loctite 2440™.
This "Next Generation" threadlocker provides:

Upgraded temperature resistance - up to 360°F
Oil tolerant curing on as-received fasteners without cleaning
Primerless performance on both inactive and active metals