TDK is also one of the developers and founding member of the BDA (Blu-Ray Disc Association). TDK’s Blu-Ray Discs have the special DURABIS hard coating formulation that protects the media surface against scratches and other contaminants that would destroy lesser discs. Imation, Sony and Verbatim BDs (Blu-ray Discs) are also available in both 25 GB and 50 GB capacities.