In addition to chromatic tuning, the app can sound reference pitches for tuning by ear. You can also use it to check pitch accuracy as you practice singing. Using the mic in your device, you can tune a guitar, bass, and other instruments like violin, cello, brass, etc. Available as a free download, the convenient app features the familiar look and intuitive display style of the best-selling TU-3 and TU-3W pedal tuner. The BOSS Tuner app brings BOSS’s leading tuning technology to your favorite iOS and Android mobile devices. Google Play App Store An authentic BOSS tuner for your smartphone or tablet