change the sound of mp3/CD/VCD/DVD into FM signal,then you can share music with others through radio.Its popular with driversSpecification FM Transmetter parameter: 1.transmitting frequency:88.1MHZ.88.3MHZ.88.5MHZ.88.7MHZ; 2.moduale method:FM 3.earphone socket:3.5mm(d) 4.Frequency tolerance:±500HZ 5.Transmitting power:200±50μw 6.Transmitting distance:8m 7.Voltage:3V AAA* 8.Electric current:70±20mA 9.Dimision:84*43*24(mm)