Bluetooth codecs: For reasons I cite in my site about Bluetooth audio codecs, we didn’t mandate the inclusion of any specific Bluetooth codec—the technology that reduces the amount of data in a digital audio file so it could stream reliably over a Bluetooth connection. It's a USB C type https://www.bluetoothspeaker.top/direct-sales-wireless-speaker-indoor-sound-box-m3-super-rgb-wireless-speaker/