TDK Blu-ray Disc 25GB Logo, Bulk-50 Piece Cakebox, Breakthrough recording technology from the only media company that's a founding member of the Blu-ray Disc Association. 25GB single-layer and 50GB dual-layer write-once versions enable massive data backups and the highest resolution HD recording. TDK's exclusive DURABIS 2 hard coating formulation protects the media surface against scratches and other contaminants that would destroy lesser discs, while the company's advanced spin coat manufacturing process and ultra-precise recording materials ensure pure recording perfection. TDK: We're making Blu-ray Discs a reality.