1、Can transmit also can receive, transmit and receive 2 in 1 designed, one key switching different device using, meet your different using requirement. 2、Hi‑Fi audio output interface, double optical fiber interface and 5mm audio interface and for RCA red white conversion interface, easy to achieve use of different amplifiers sound equipment. 3、Intelligence identifies sound quality for APTX , machine body front respectively equipped for APTX/APTXLL/APTXHD/AAC/SBC，audio format constant bright light，efficient recognition of corresponding transmission audio. 4、Can continue using about 1 day, built‑in 600mA lithium battery, support charging while using. 5、Small and exquisite one hand control, convenient to carry, two stage designed, frosted and mirror surface combination, more fashionable aesthetic. 6、TX：Transmit mode convert TV/PC/projector to Bluetooth wireless transmission. RX：Receive mode convert earphone/sound/amplifier/vehicle‑mounted to Bluetooth wireless transmission. 1 x Optical Fiber Cable1 x Red White for RCA Cable1 x 3.5mm Audio Cable1 x Charging Cable1 x Manual 1 x Bluetooth Transceiver Condition: 100% Brand NewItem Type: Bluetooth 5.0 Receiver Transmitter 2 In 1 AdapterModel: XU21Material: ABSColor: BlackBluetooth Chip：CSR8675Bluetooth Protocol Support：RX：A2DP AVRCP TX：A2DPTransmission Distance：> 10M（Open Area）Battery Standard: 600MA （Lithium Battery）Using Time: RX> 18H TX> 22HCharging Time: About 3HCharging Voltage：DC 5VInput/Output Connection Mode: SPDIF， 3.5MM Stereo Audio InterfaceCoder Decoder: TX：apt X HD，apt X Low Delay，apt X，SBC RX：apt X HD，apt X Low Latency，apt X，SBC，ACCWeight: Approx. 145g