Answer: verniers

AnswerCrossword Clue
verniersequipped with a vernier
verniersVERNIER, an auxiliary scale that gives fractional readings
vernierssmall, movable, graduated scale running parallel to the fixed graduated scale of a sextant, theodolite, barometer, etc., and used for measuring a fractional part of one of the divisions of the fixed scale
verniersauxiliary device for giving a piece of apparatus a higher adjustment accuracy