The scientific complement to NASA's Hubble Space Telescope, the Webb assembled in a Class 10,000 cleanroom at NASA's Goddard Space Flight Center. (cemag.us)
Checkweighers are used in cleanrooms, dry atmosphere environments, wet environments, produce barns, food processing, drug processing, etc.. (en.wikipedia.org)
The microshutters were moved into a NASA Goddard cleanroom for testing to verify they work correctly before being installed in the Webb's Near Infrared Spectrograph (NIRSpec) instrument. (sciencedaily.com)