It makes very good 1:1 Copies , but not the exact. Because to make an 1:1 Copy u need the same burner and the same cd the software has been burned on. Because of the starting point. Every burner makes it on different cds in an otherway. I mean that it starts that point later. Any CD-rom or s.th. like that don't notice that. and for it its no differenz. So the CD works , but it isn't a real 1:1 Copy, I think.