Stay in tune with this chromatic tuner and pitch pipe for your musical instrument. It tunes not only with guitars, bass guitars, and banjos, but also many other instruments and even with your voice. (Just sing into it!) The tuner works with the built-in microphone on the iPhone, and with any audio that comes in from an external source, such as the microphone on a headset, on the iPhone and iPod touch second generation. The built-in pitch pipe lets you play a reference tone for tuning by ear.
