Samson's CT16 Clip-On Tuner attaches to the headstock of guitars and basses for hands-free tuning. It uses a vibration-based piezo sensor with A410-450 Hz calibration and supports chromatic, guitar, bass, violin, ukulele C and ukulele D modes, plus flat tuning. A large LCD display and a 360-degree clip provide easy viewing from any angle in varied lighting. Powered by a single CR2032 battery (included), with over 20 hours of operation.