[QC3.0 Quick Charging] The FM transmitter has two USB charging ports, QC3.0/3.4A interface, advanced quick charging technology, which can quickly charge the mobile phone and shorten the charging time. Wait for charging. Bluetooth 5.0 technologyBuilt-in Bluetooth adapter high-performance decoding module, wireless 5.0 lossless transmission, eliminating interference, low noise, shocking high-definition sound quality, giving you better sound experience. [LED Voltage] Automatic Bluetooth FM transmitter with LED voltage display, real-time voltage data monitoring, protect your device more comprehensively. 3 Music Play ModesThe car Bluetooth adapter supports U and floppy/TF card play music. Plug and play, enjoy more high-quality high-definition audio sources, suitable for 12-24V mainstream models, suitable for iPhone, iPad, Samsung, tablets and other Bluetooth devices, making your trip more comfortable. < p>Hands-free call voice navigationBluetooth transmitter built-in microphone, one-key answering, hands-free and safer driving. One-key operation, quick, convenient and safe. You can get clear voice navigation through the mobile app to make your driving safer. Suggestion for use1. Make sure the FM frequency you choose is an empty channel with no local radio signal). 2. You must set the frequency of the FM transmitter to the same frequency as the car radio. 3. Try setting the car radio volume to medium to minimize noise pollution.