Tunes2Go 3-In-1 Multifunctional Car FM Transmitter (Black/Blue/Silver) Detachable In-Car FM Transmitter, transmit range: 87.5 to 108.0MHz Portable MP3 Player and FM Radio with built-in 4G memory Support MP3 and WMA format of music Car charger; additional USB port to charge mobile phones, MP3 players or other devices while charging the main unit; output 5V/2A Build-in rechargeable battery: can play music up to 6 hours after fully charged