Grease applicator - GIF

[Toolmaker51]

We've all greased bearings. By gun, thrown hard into a bucket, or fingers of course.
A company [Odetics, Anaheim CA] built ultra high grade reel to reel tape decks for various space programs, US and abroad. Sturdily engineered to withstand G force of rocket launch.
These had several ball bearings, about 1.5 and 4mm bore. These were cleaned of assembly grease 101% and regreased with specialized lube.
Under a microscope.
Clean room of course, in an electronic lab scale.
With a precisely metered air driven syringe and needle.
Each ball [8-10?] got a milli-milli gram right where ball and cage met. 1 pin point dot.