Tunes2Go 4-In-1 Multifunctional Car FM Transmitter with MP3 Player/USB Charger (Black/Blue) 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 Can be used as a USB Flash Drive Build-in rechargeable battery: can play music up to 6 hours after fully charged