Features: 1) Download file: connect this product to computer through attached cable line, then download MP3, WMA, an ASF files to the catalogue root 2) Plug the unit into cigarette lighter of your car directly, the red indicator lamp keeps lighting. Several seconds later, this product will play automatically. Indicator lamp becomes glinting 3) Press the button CH to select FM channel according to the FM indicator lamp 4) Tune the frequency of car stereo