Smart QC 3.0 Quick ChargeBluetooth FM Transmitter has two USB ports, which can charge two devices at the same time. One is a USB QC 3.0 port for fast charging, which is 4 times faster than a standard charger. (Compatible: QC2.0, FCP Hua Wei, Samsung and HTC.) At maximum power, the charging efficiency is over 80%, so your device can be fully charged in a short time.Bluetooth Hands-freeAdvanced Bluetooth 4.2 technology enables more stable connection and faster transmission. When connected to Bluetooth, the built-in microphone with CVC noise reduction technology gives you a clear speaker. Just press one button to accept/end/reject call/set last call. Drive safely.Multi-Music Playback ModesEnjoy lossless stereo music transmission. Allows playing music via Bluetooth connection / USB flash drive (64G) / TF card (64G), this bluetooth fm transmitter will provide more stereo and duplex sound with its high fidelity system. Supporting MP3/WMA/WAV/FLAC/APE format files. It gives you wonderful car music and makes your journey more fun.Easy to Use-Plug it into the cigarette lighter socket. - Turn on the car FM radio and select the empty frequency. -Set the same frequency as the transmitter(87.5-108.0MHz). -Connect your phone to the transmitter (named C57) via Bluetooth. Then you can listen to music without interruption.Multiple ProtectionBluetooth FM transmitter is equipped with overcurrent protection, overvoltage protection, short circuit protection, control temperature smart.