Bluetooth 5.0 transmitter receiver: The Bluetooth transmitter transmits audio wirelessly to a Bluetooth headset/speaker. The Bluetooth receiver turns a conventional speaker into a Bluetooth speaker. Suitable for devices with 3.5mm connector, only supports Bluetooth 5.0. When connecting, please place the product close to the paired device for better connection, and use USB charging data when using on a PC. In transmit mode, make sure the headset or speaker is in a state where Bluetooth can search for a connection. The latest Bluetooth transmitter When the USB charging data cable is plugged into the PC, it acts as a transmitter to transmit audio, making the PC Bluetooth capable. Correct earbud wear and software updates can help reduce noise problems. Make sure the earbuds and phone or any other device have the latest software version installed. Products that do not work may have a low initial battery charge. Please try using them after they have been fully charged. [Always on The Bluetooth 3-in-1 adapter continues to stream even when charging. The built-in battery lasts up to 10 hours - always enjoy your favourite wireless content. The red indicator light is always on when charging, the volume buttons do not wor and the light turns off when charging is complete. Common ground current noise may cause noise. We recommend not using it while it is charging to avoid current noise. It is best to wait until it is fully charged before using it. Bluetooth Everywhere With the latest V5.0 EDR technology, our wireless audio adapters allow for a more stable connection with devices. Only 1 device can be paired at a time, it will not transmit to multiple devices and the distance between the Bluetooth adapter and your Bluetooth device should be within 50 feet. The charging standard for this product is 5V1A. Please do not use a high current adapter to charge the product. Note: When transferring audio directly to your computer using the USB charging cable, you do not need to use a 3.5mm audio cable to connect to your computer. When transferring audio directly to the computer using the USB cable, the volume of the computersystem cannot be adjusted, only the volume of the software can be played. When using it, be careful whether you are trying to receive or transmit. Don't get it wrong, RX is receive and TX is transmit, if you connect it wrong there will be no sound.