The BOSS Tuner app brings BOSS’s trusted and world-renowned chromatic tuning technology to Android mobile devices. Available as a free download, the convenient app features the familiar look and intuitive display style of the best-selling TU-3 / TU-3W pedal tuner. Using the mic in your Android device, you can tune a guitar, bass and other instruments like violin, cello, brass, etc. Features - Provides hands-free chromatic tuning for a variety of instruments - Audible reference pitch function f