The speaker works by using CSR four.0 Bluetooth for high quality music streaming and you can connect the speaker to your smartphone or tablet devices. The speaker comes with a built-in rechargeable 3600mAh battery and charges through the micro USB port. The speaker also come with a built-in UNC https://www.bluetoothspeaker.top/retro-gift-boombox-with-bluetooth-speaker-am-fm-radio-player/