A metronome is a device which indicates a particular pulse to musicians. Clavis Pianos' collection includes mechanical metronomes by Wittner as well as a digital metronome.
A mechanical metronome consists of a clockwork escapement with an inverted pendulum (physics). The pendulum swings back and forth at a regular interval and produces two clearly audible ‘clicks’ per cycle. The interval duration can be changed by adjusting the small weight on the pendulum. Some metronomes can also play a bell sound to indicate the first beat of a measure. Both the clicks and the pendulum’s regular movement help pianists determine the right pace and stick to it.
A digital metronome produces an electronic ‘click’ or other sound and is battery-operated.