Snark All Instrument Tuner - model no. SN-2
 

SN-2 is able to detect an extended frequency range and
can be used for all instruments including guitar. 

It's chromatic, and it senses the vibrations of the instrument they are attached to.

In addition, SN-2 has an internal microphone that
can be used for note detection in iieu of the vibration sensor. 

Use the MIC/VIB switch on the SN-2 to select which note detection means you choose.