A submicron scanner
A sub-micron scanner was a type of scanner used as engineering tool used to scan power cells.
In 2372, Lieutenant B'Elanna Torres used one while trying to construct a prototype Automated Personnel Unit. (VOY: "Prototype")
The script described the prop as "a high-tech tool". The prop itself was originally created for the movie Men in Black (as an alien handgun) and was later re-used as a Srivani medical device in "Scientific Method".