Description 1. Bluetooth 5. 0 and dual USB ports less power consumption, transmit signal faster and wider supported by the latest Bluetooth 5. 0 technology. Charging 2 devices supported by the 2 USB charging ports ( 5V or 3. 4A ). Support to read Micro SD 2. Unique bass switch when playing music, press the B button to add more bass and enjoy more powerful music. Stream music from your smart phone to the car FM stereo system via Bluetooth. 3. Clear hands-free calling The built-in microphone provides you with an amazing hands-free function after connecting Bluetooth. Answering or redialing or dismissing or ending call just simply click a button. 4. Multiple Protection comes with built-in smart IC, over-current protection, over-voltage protection, Intelligent temperature control, short circuit protection. The FM transmitter effectively prevents multiple unsafe problems. 5. How to avoid interference keep the frequency of the two(car radio and FM transmitter) far apart when not in using, so as to avoid interference. Please find a blank frequency on your car radio first before plugging it to your cigarette lighter socket. 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.