1) Supports playing MP3 and WMA music format 2) With mini B USB plug, direct connect to computer by USB cable 3) Supports backup important files and transport any kind of file from one computer to another 4) No drive needs above the Win98 system. 5) Built-in lithium battery MP3 WITH BLUETOOTH FUNCTION OPTIONAL Sunglasses function: 1) Maintain critical clarity at all angles of vision that maximize protection against sun, wind and side impact 2) Frame material offers all-day comfort 3) The flip-up lenses block 100% of all UVA, UVB, UVC and harmful blue light