Features: Made of alloy, strong and durable. Guitar Capo Quick Change Capo Tuner is not only a professional capo but also a professional tuner. Tuner with high sensitivity,more accurate,precise,convenient and rapid. The tuner detects sound automatically, and shows the note name accordingly. When the note name shown on the screen stay the same as the sound from your instrument, and the accuracy bar points to calibration "0" vertically, and the LED light turns green. If no operation or no signal input for 30 seconds, it will turn to power-saving mode automatically, and the back light will be off. When there is operation or signal input, the back light will be on again. Perfect for acoustic guitar and electric guitar.