 The Blu-ray Disc physical specifications were completed in 2004.In January 2005, TDK announced that they had now developed an ultra-hard yet very thin polymer coating ("Durabis") for Blu-ray Discs; this was a significant technical advance because a far tougher protection was desired in the consumer market to protect bare discs against scratching and damage compared to DVD, while technically Blu-ray Disc required a much "thinner" layer for the denser and higher frequency blue laser.Cartridges, originally used for scratch protection, were no longer necessary and were scrapped.