Magnifying glass
A magnifying glass was a handheld object used to examine small things more closely.

Henry Starling had a magnifying glass in his Los Angeles office at Chronowerx Industries.  The Doctor picked up this object in 1996 and used it to take a closer look at his holographic hand. ()

When Data had been introduced to the fictional character of Sherlock Holmes in 2364, he started using a pipe and magnifying glass to mimic the character. ()

Inspired by Talur's magnifying glass, Data constructed a microscope to help determine the cause of the mysterious illness shared by the villagers on Barkon IV. ()

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Science
Household tools