Boss TU-03 Clip on chromatic tuner with metronome. Compact and simple to use, the TU-03 puts 2 essential music tools within easy reach. It combines a chromatic tuner and metronome in one device that clips onto the headstock of nearly any stringed instrument, providing instant-access convenience everywhere you play. Packed with deep features not typically found in clip-on units, the TU-03 offers fast and accurate tuning performance with 5 different modes, plus advanced metronome functionality with a built-in speaker and numerous pattern/beat variations. The tempo is easily adjustable from 30-250 BPM. Flat and double-flat tunings are available as well, and the overall reference pitch is adjustable from 430-450 Hz.