The Korg TM-40 offers tuner and metronome functions in one compact, digital machine. Use the tuner and metronome simultaneously or independently. It has a large LCD-type needle and LED indicators that show pitch deviation, and LED blinks to indicate the tempo. It produces tuning reference pitches, and has a wide calibration adjustment range, and a jack for optional pick-up mic. It also has memory backup and auto power off. Uses 2 AAA batteries (included).