2-In-1 Design The Bluetooth adapter combines a bluetooth audio transmitter and receiver in one with a 3.5mm aux jack. The latest Bluetooth V4.1 chip imported from the UK. The Bluetooth connection is more stable and the wireless range is more than 33 feet. Easy pairing and compatibility with 99.9% Bluetooth devices. Updated Bluetooth 4.1 ensures strong singal transmission, high sound quality, less crackling, hissing or sound deterioration Double connection When used as a Bluetooth transmitter, it can be paired with two Bluetooth receivers, such as headphones and speakers at the same time. If you work as a Bluetooth receiver, it can still be paired with two smartphones or tablets, but the receiver can only receive audio from one of the two paired devices. note that the sbc codec only supports in conjunction with two devices at the same time