... its 4-in-1 multifunctions: MP3 player, MP4 player, SD Card Reader, FM Transmitter. Car MP3/MP4 Player SD FM Transmitter ... its 4-in-1 multifunctions: MP3 player, MP4 player, SD Card Reader, FM Transmitter.Features:Multifunctions: MP3 player, MP4 player, SD ... wireless transmission.With 206 FM Channels.Support SD/MMC expansion card (1GB-8GB)(SD Card is not included)Without built-in memoryEasy operation ...