A metronome is a device that produces an audible click or other sound at a regular interval that can be set by the user, typically in beats per minute Stock Photo -
Metronome - Wikipedia
Metronome (Shaker), BPM 60-89 by My Drummer Buddy on Apple Music
Metronome Beats Pro:Amazon.com:Appstore for Android
Piano Q&A: All about tempo markings in music - PianoTV.net
60 BPM Metronome - Adagio - 1080p - TICK and FLASH, Digital, Beats per Minute - YouTube