1Built-in 7V 300mAh rechargeable lithium battery, support up to 8 hours of working time 2The red LED indicator indicates that the device is charging, and the green LED indicator lights up to indicate that the device is fully charged. Two indicator lights indicate that the device is fully charged, and one LED indicator means less than 75% remaining power 3Headphone mini plug amplifier with distortion effect. Just plug music into the guitar, you can enjoy music at home or outdoors 4Function knob can control tone, distortion, volume adjustment. The AUX in the jack allows you to use it with a mobile phone or MP3 player. There is a 5 mm headphone jack 5The design is small and easy to carry. You can put in your pocket when you are out, plug and play. No matter where you go, you can play the guitar freely anytimeItem Type: Plug AmpMaterial: ABS + electronicsBattery Type: 3.7V 300mAh rechargeable lithium batteryHeadphone Jack: Approx. 3.5mm / 0.1inSize: Approx. 8.3 x 7.9 x 2.8cm / 3.3 x 3.1 x 1.1in