Our guitar tuner has a built-in rechargeable battery. You can use the USB cable that comes with your PC or power bank to quickly charge it. After a single charge, it can be used continuously for more than 10 hours. After 5 minutes of no signal, the violin tuner can automatically shut down to save energy; high-sensitivity vibration-based tuning, even in the presence of background noise, can ensure that your instrument is accurately tuned in the flash. The clip on the guitar tuner has a note key function, which can meet the needs of most professional guitarists. You can place the screen in any way you like. The ukulele tuner has almost no borders and has a large LCD color display that can be easily read even in dark environments. When the device is in G (guitar) tuning mode, short press this button to switch between guitar tuning (DROP D, OPEN G, OPEN D, OPEN E) and flat tuning (b, 2b). Specification: Color: show as pictures. Material: ABS. Size: 4.9x2.6x4cm. A4 value range: 440Hz. Tuning items: Twelve equal temperament, guitar, violin, ukulele. Tuning accuracy: 1 Cent. Battery type: built-in rechargeable lithium battery. Note: There might be a bit color distortions due to different computer resolutions. There might be a slight errors due to different hand measurement. Package Included: 1 x Tuner. 1 x manual. 1 x certificate of conformity. 1 x Micro USB interface charging cable