1. Divided into three categories, precious metals, other metals and leather. 2. Leather from Japan website, part of the collection network, part of the editing and translation, please correct me shortcomings. 3. Roughly known as the use of strap material Daquan, deficiencies, but also make up brothers! 4. There are pictures of leather, the other without picture, picture 1 for leather pictures in 1-2, and so on, a total of 25 categories of leather, 13 pictures. 1, precious metal material: (1) Platinum Is a rare and expensive natural pure white metal, one of the rarest jewelery precious metals in the world, supplied annually