Neewer Traditional Wind Up Mechanical Metronome for Piano Guitar Bass Drum Violin and Other Musical Instruments NW-707(Blue) Perfect practice tool to establishes regular, metrical beats to help you play rhythms at a proper pace Produce a clear and loud sound for use when practicing piano, violin, guitar, bass, drums and other musical instruments No battery required, the mechanical metronome uses a winding mechanism for power to produce metrical beats Tempo range:40-208 BPM Beat selection: 0, 2, 3, 4, 6