Bluetooth 2-in-1 Audio Transmitter and Receiver-Black. Bluetooth 4.1 Version with APT-X Support - Maximum 10m pairing distance range with APT-X support, transmit and receive audio without delay. Transmitter (TX) Mode - In TX mode, you can stream your non-Bluetooth enabled TV/stereo audio to 2 Bluetooth headphones or speakers simultaneously. Receive (RX) Mode - In RX mode, you can stream audio wirelessly from your computer, smartphone or tablet to any non-Bluetooth audio device with an AUX IN (3.5mm) or SPDIF OUT (Optical) port like speaker docks, stereos, receivers and car stereos. 2-in-1 Design, More Connection Options - Transmitter and Receiver two modes with the flip of the switch. Supports AUX and SPDIF connections. Long Battery Life - TX, RX Working time (AUX): About 15 hours, TX, RX Working time (SPDIF): About 12 hours.