No need of external power supply, just enjoy the music anytime anywhere. Compact and Delicate Design: Wooden shell design, very delicate and beautiful; compact size and with top handle, the guitar amplifier can be easily carried anywhere and is quite suitable for travel use. Specifications: Model: AC-25 Rated Power: 25W Speaker Unit: 6.5 inch 4? Power Supply: Built-in 11.1V 2600mAH Lithium Battery Recharge Socket: Type-C 5V/8A BT Version: 5.0, 15m effective distance Item Size: 26.8 18.5 19.5cm/ 10.6 7.3 7.7in Item Weight: 3200g/ 7.1lbs Package Size: 30 24.5 23.5cm / 11.81 9.65 9.25in Package Weight: 3517g / 7.75lbs Note: Guitar showed in the picture is not included Package List: I7100 1 Amplifier 1 USB Charging Cable 1 Hand Strap 1 Users' Manual(English & French & German & Italian & Spanish & Japanese).