Korg Clip On Contact Microphone
The Korg CM-100L is a contact microphone you can use to extend the reach of your electronic tuner, for more accurate pitch detection. The clip-on microphone can be used to get more sensitive readings on your guitar, bass, or other instrument, while the tuner itself can be positioned anywhere for easier reading.
It's easy to use. Just plug the cord into the 1/4-inch jack port on your Korg tuner, then clip the CM-100L microphone onto the edge of the sound hole or f-hole of any acoustic guitars, basses, mandolins, and violins. Turn on your tuner, and your are ready to start tuning. No batteries needed. It makes a great accessory for your Korg tuner.
Suggetion: Why not get one when you buy a tuner?