The MT-50 Quartz Metronome from Wittner is a battery operated electronic metronome with a tempo range from 40 to 208 BPM (beats per minute). It can be used by musicians and students for applications such as sight-reading, rehearsals, ensemble playing, and more. It features a standard A=440 Hz reference tone for tuning and a click sound and/or light-beat indicator to mark tempo. A built-in wire stand allows convenient upright positioning and a black earphone to monitor tempo privately is also included. It is powered by a 9V battery (not included).