Play-on Chromatic Tuner for Guitar, Bass, Violin and Other Instruments with Extra Battery Comes with two batteries, 1 installed and 1 extra Two modes, Clip-on(Vibrate), and Free-Standing(Mic) 4 Instrument settings, Guitar, Bass, Violin and Chromatic Screen light turns green when the string is in tune, and the meter is in the middle 360 Degree Rotation on the clip for optimal visibility