The D'Addario Headstock Tuner Clip-on Tuner guitars, basses and other stringed instruments with precision. With its highly sensitive piezo and color display, it allows you to easily and precisely tune even in the noisiest and darkest environments where others fail. The tuner has a screen that automatically turns on and off when opened and turns off when closed. The screen rotates 360 degrees to fit all types of right- and left-handed guitars.