Bluetooth 5.1 Sound Receiver Transmitter 2 in 1 Noise Reduction Low Latency Plug and Play Portable Bluetooth Car Adapter                       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, one‑key 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 Transmitter  Material: ABS  Size: Approx. 60 x 20mm/2.4 x 0.8in  Bluetooth Version: 5.1  Connection Range: Approx. 15m/49.2ft  Interface: 3.5mm Sound Interface  Frequency Response Range: 10Hz-20KHz  Signal to Noise Ratio: Less Than 110dB  Function: Receiver Transmitter 2 in 1  Built in Battery Type: Li ion Battery  Battery Capacity: 140mAh  Battery Model: 401224                    Package List:      1 x Host      1 x USB to Type C Charging Cable      1 x 3.5mm Sound Head      1 x Chinese and English Manual             Note:         Please allow some errors due to manual measurement.                   How to use:       RX receive mode:           1. Press and hold the power button for 3 seconds to power on:           2. Turn the mode key to the RX position, the blue light flashes;           3. Turn on the Bluetooth of the mobile phone to search for B28, click connect, and the blue light is always on after connecting.           TX transmit mode:           1. Press and hold the power button for 3 seconds to power on:           2. Turn the mode key to the TX position, the red light flashes;           3. Turn on the receiving device that needs to be paired, and make it into the pairing state, the adapter will automatically connect, and the red light will be on after connecting.