Loctite Threadlocker 243 surface insensitive-medium strength general-purpose, primerless, blue stick threadlocker with improved oil tolerance. For fasteners between 1/4-Inch to 3/4-Inch (6 mm to 20 mm). Parts can be separated using hand tools. Product typical applications are rocker studs, rocker adjustment bolts, bolts on valve and cam covers, oil pans, disc brake calipers, intakes and alternators, pulley assemblies and much more. Invented by Henkel as a revolutionary method to positively lock and seal threaded fasteners, Loctite threadlocker adhesives are used in a wide range of applications from delicate fuel injection components to heavy-duty transmission and engine assemblies. Specified by automotive OEM's and approved for use on factory assembly lines, threadlockers work by filling the spaces between threads. The result is a secure, one-piece assembly that will not loosen under stress.