... stored in MP3 / WMA files.2) connect with computer reads, written to the file to MMC/SD/TF ... 8) connect usb------Product specifications and parameters1) support the computer system: Windows, win2000, win XP, win Vista2) the USB ... 3.7 V 150 mah);8) charging power supply: computer USB port DC5V; DC 5 V (500 MA) ... and the machine, it can be on the computer files downloaded to insert the machine SD or MMC ...