Product color: blue Model name: T3 Battery: Lithium-ion battery is required. (include) Quantity: 1Pcs Package content: 1*T3 Bluetooth receiver transmitter 1.RX & TX MODE: The Bluetooth transceiver is a smart Bluetooth transmitter and receiver, supporting both Bluetooth receiving and transmitting, namely RX and TX mode. RX mode turns your old wired headphones, CD player, speakers or car/truck into Bluetooth function enabled. TX mode equips your desktop, TV and TV BOX with Bluetooth so that these equipment are able to connect your Bluetooth earphones speakers. 2.MICROPHONE: Phone calls can be listened and answered easily and safely through the cars stereo and the car audio adapters microphone, no need to dangerously take cellphone out from pocket or stand. Long press the phone/play key to activate the voice assistant of cellphone and talk to Ewin audio adapters mic to let your cellphone change a song, make a call, send a message etc, without using cellphone being much safer. 3.1 TO 2: In TX mode, the Bluetooth 5.1 transmitter can be paired with two Bluetooth headphones/speakers simultaneously. 4.LOW DELAY PURE STEREO: Aptx and DSP codec technology contributes to a richer and deeper stereo experience with low latency and high fidelity. Enjoy CD-like audio quality all the time. 5.ALWAYS ON: 3-1 wireless audio adapter can still work while charging. Built in batteries for up to 7-8 hours use and automatic shutdown after no connection for 5 minutes.