Manufacturers rate the quality of blank recordable disc media in terms of grade. When a disc is referred to as being grade A, it means the disc is the highest quality available and it will have few imperfections and provide you with the lowest rejection rate. Grade B media is a step down and has not passed the same quality standards required to be grade A. Lower grade discs will produce far more errors and may not have the same storage life as higher "grade A" media. To buy Grade A media go to www.cdrom2go.