A "depth gauge micrometer" is used by engineers. A depth gauge
micrometer is a precision instrument used to measure various depths
of different items.
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The purpose of a depth gauge is to measure the depth of water.
It is used by scuba divers to make sure they don't go too deep
because the deeper they go the more pressure the water is.
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A device to measure the tire's thread depth.
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Depth perception is utilized to gauge one's distance from an
obstacle.