The Boss TU-03 Clip-On Tuner/Metronome is a compact chromatic tuner which simply clipped to the headstock of standard stringed instruments and quickly and accurately detects pitch based on the instrument's resonance, even in the loudest environments. In addition, an extensive metronome section is available for practicing timing, with 8x different patterns and 10x beat variations for every style. The Boss TU-03's illuminated display makes it easy to read even on dark stages.