Answer: metronomes

AnswerCrossword Clue
METRONOMESMusic timekeepers
METRONOMESBeat keepers
METRONOMESTimekeepers.
METRONOMESTime keepers
METRONOMESInstruments for Horowitz
METRONOMESMusical timekeeper
metronomesMETRONOME, a mechanical device which indicates the exact tempo of a piece of music by producing a clicking sound from a pendulum with an adjustable period of swing
metronomesA device used by musicians that marks time at a selected rate by giving a regular tick