Using Bluetooth 5.0 technology, it has hands-free call function and can plug and play. Bluetooth transmission mode (TX) means to convert wired audio into Bluetooth signal and transmit it to the Bluetooth device for output. The Bluetooth receiving mode (RX) refers to receiving Bluetooth signals and transmitting them to wired audio through the Bluetooth connection. With high-resolution restoration of lossless sound quality, you can listen to music on your phone. With low power consumption and high rate stable signal transmission, let you listen to songs more smoothly. Item Name: Bluetooth Audio Adapter Material: ABS Product Model: C28 Battery Capacity: 140Amh(Included) Working Range: 10m(without Obstacles) Charging Time: 1H Use Time: 4H Applicable Type: Computer, TV, Projector(Transmission Mode)/Speaker, Earphone(Receiving Mode) Features: Hands-Free Call, Plug and Play, Low Power Consumption, Stable Signal Transmission Size: 5.95cm x 2.2cm x 1.2cm/2.34" x 0.87" x 0.47" (Approx.) Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Bluetooth Audio Adapter 1 x Charging Cable 1 x User Manual 1 x 3.5mm Audio Cable