It's not a zip drive. It's a removable file storage. I know I said hard drive previously, but file storage sounds better. Difference? no compreesion, unless you put it in a zip file. Also, no cumbersome software or hardware, like zip drives. With WinXP the software loads itself, otherwise you get a small disk with it. Size wise, I assume you could get just about any size. Mine was given to me at Autodesk University. It's 64MB. I wouldn't want to put AutoCAD on it, but I don't think it would have any licensing issues as long as you don't let other users use it while you're using it.