The Universal Chromatic Tuner is a working musician"s tuner with a twist - a patent pending fold-out tuning bracket hangs the tuner from the sound hole of an acoustic guitar for hands-free tuning. With a wide range of accuracy and a built-in mic, the Universal Chromatic Tuner is a great choice for tuning anything from a 5-string bass all the way up to a mandolin - It works great with band and orchestral wind, brass, and stringed instruments as well. Features: Dual-mode operation for auto or manual tuning Fold-out rubberized, patented tuning bracket improves tuning performance LCD and LED displays for tuning in both well-lit and dark environments A440 calibrated. May be user calibrated to any pitch from A335 to A445