This means that you have one of the first 4000 Quattro's released before December 2001. These devices were built for use with the Macintosh operating system only due to the chip set installed on these units, thus the Mac Sticker. Any attempt to use these devices on a PC is done so at the user's own risk as we do not recommend any attempts to make the MAC Quattro work withthe PC. These units are not upgradeable to the multi-platform version.