Feature:1. 2 in 1 Design: This 2 in 1 sound adapter, one button control, easily switch between transmit and receive modes. Easily enable Bluetooth on your TV or projector using Transmitter mode via the 3.5mm sound jack.2. Bluetooth 5.1: The latest version 5.1 Bluetooth wireless communication standard, low latency, noise reduction, improved speed and range, 15m transmission distance, large signal range coverage, fast and stable connection, and enjoy wireless.3. Portable and Easy to Operate: The Bluetooth sound adapter features a slim design with a minimal footprint and with a 3.5mm plug, it is small, lightweight and portable. Plug and play, easy to set up, onekey operation, clear status indicator.4. Multifunctional: This Bluetooth car adapter enables hands free Bluetooth calling and navigation voice through the built in microphone, and has a built in 140mAh lithium ion rechargeable battery for 4 hours of continuous use.5. Scope of Application: This Bluetooth 5.1 sound receiver transmitter Lavalier design, firm and not easy to fall, easily add Bluetooth to your car sound system, home sound, speakers, wired headphones through the 3.5mm AUX socket.Specification:Item Type: Bluetooth Sound Receiver TransmitterMaterial: ABSSize: Approx. 60 x 20mm or 2.4 x 0.8inBluetooth Version: 5.1Connection Range: Approx. 15m or 49.2ftInterface: 3.5mm Sound InterfaceFrequency Response Range: 10Hz-20KHzSignal to Noise Ratio: Less Than 110dBFunction: Receiver Transmitter 2 in 1Built in Battery Type: Li ion BatteryBattery Capacity: 140mAhBattery Model: 401224.Package List:1 x Host1 x USB to Type C Charging Cable1 x 3.5mm Sound Head1 x Chinese and English ManualNote:Please allow some errors due to manual measurement.