MMUSC Wireless in-Car Bluetooth FM Transmitter with Music Control, Hands-Free Calling, and USB Charging 5V/1A Output Connects with your smartphone/MP3 player via Bluetooth Transmits your favorite tunes from iPhone or MP3 players to your cars FM stereo system. Built-in USB port to charge your phone or other device while driving Hands-free calling function allows you to talk through your car stereo safely while driving, Built-in echo cancellation technology ensures optimal sound during calls Full FM radio frequency range from 88.1 to 107.9MHz, can satisfy your need and preference for different frequency channels.