BOSS TU-88WH Micro Monitor & Tuner for Guitar and Bass (White) Built-in headphone amp lets you tune, warm up, and check your effects in private Built-in metronome with selectable rhythmic patterns and volume control Headphone amp with speaker simulator for monitoring effects Three tuning modes (Chromatic, Guitar, Bass), Flat Tuning function, and ACCU-PITCH verification with an audible beep MIX IN allows jamming with an external music-playback device (iPod, etc.)