Product features: Support Bluetooth hands-free call, convenient and safe on the phone. Have CVC noise processing, has the wind noise suppression function, full-duplex call technology. High quality A2DP streaming. Support two cell phone connection. Support USB/SD card MP3 format music playing. Play music,long press PLAY button transmitter 4 seconds can realize not code replay function. With multi-function remote control. Can realize number song selection and choose frequency. Instruction on how to use your FM transmitter Insert this FM transmitter into your vehicle’s cigarette or power port. Tune to your radion to a desired FM frequency,then match that same frequency on to the FM transmitter by using the buttons on the unit or on the remote control. Plug  your compatible SD Card into the SD port or USB Flash Drive into the USB port of your FM Transmitter,or connect your other compatible Drive using the Audio cable. For other compatible music devices or your mp3/,mp4 players,use the supplied audio line cable to connect from the other devices’s “line out”to the FM Transmitter “line in”.When using an external device,all functions will be controlled by the external devise,neither the transmitter nor its remote control. Enjoy!