D'Addario PW-CT-13 Micro Clip-on Headstock Tuner

Using a highly sensitive piezo censor and large multi-color display, the PW-CT-13 Clip-On Headstock Tuner allows you to tune easily and accurately in noisy and dimly lit environments where many other tuners fail. The tuner features a flip-up display that automatically powers the tuner on when opened and off when closed. The 360° rotatable display allows for use on right-handed and left-handed instruments.

It has chromatic mode only, so it relies on the used knowing their chromatic scale!