The collection consists of two new references, each a limited edition and each powered by a Seiko Spring Drive GMT automatic mechanical movement. These models are housed in a five-part case with an inner case made from high-intensity titanium and an outer shell and bezel made from zirconia ceramic which is stronger and tougher than any other fine ceramic. The case is also 25 percent lighter than stainless steel despite being seven times harder than that material on the Vickers scale, and is highly resistant to scratches. Many of the traditional hallmarks of the Grand Seiko collection are present on the new models, including the clear ridges on the case facets, the diamond-cut hands and markers, and the gold lion emblem on the movements’ winding rotors. The movement is visible through a screwed, see-through sapphire caseback. They are all limited edition for 500 pieces only.