Wittner Metronomes are some of the finest Metronomes in the World! The Wittner Metronome is plastic. It is a wind-up metronome that does not require batteries. Utilizing a pendulum arm. It has a plastic cover and features a bell sound to accent the start of a count. Speeds are from a slow 40 beats per minute to a very fast 208 beats per minute w/ accents appropriate to 2/4, 3/4, 4/4 and 6/8.