An X-ray of Harrison "Jack" Schmitt's Apollo 17 lunar glove, produced by ILC Industries, shows ball bearings around the wrist. Ball bearings and aluminum rings were part of the locking system that fastened the glove to the arm of the spacesuit. The rings were overlaid with gauntlet, an extended cuff covering part of the forearm, so that the metal didn't become too hot in the sun or become coated with lunar dust.

X-ray by Roland Cunningham and Mark Avino.