Rechargeable via USB Charging CableOur guitar tuner is built with a rechargeable battery inside, never need a replacement button battery, and also very eco-friendly. Recharges quickly with the included USB cable on your PC or mobile power bank, and lasts for over 10 hours of continuous use on a single charge. The violin tuner saves energy by automatically powering off after 5 minutes of signal.Key Function: The clip-on guitar tuner has a note key function that meets the needs of most professional guitar players. When the unit is in G (Guitar) mode, short press this button to toggle between Guitar Tuning (DROP D, OPEN G, OPEN D, OPEN E) and Flat Tuning (B, BB). With this function, you can play more songs.High Sensitivity & Incredible Accuracy: Highly sensitive vibration-based tuning ensures your instrument is tuned precisely in a snap, even with background noise. Unlike other cheap tuners, this guitar tuner quickly and flawlessly reads the low E bass string without getting in and out.Compact Size & Large Display: The ukulele tuner is nearly frameless with a large LCD color display, making it very easy to read even in dark surroundings. With a 360 degree rotating clip, you can position the screen as you wish. The tuner clip is well designed and small enough to fit in your pocket or on the end of the guitar case.GREAT GIFT FOR STRINGED INSTRUMENT PLAYERS: This violin tuner features four tuning modes (chromatic, guitar, violin, ukulele) covering a wide range of instruments including mandolin, banjo and almost any stringed instrument acoustic and electric strings. Packed in an elegant gift box to surprise the one you love