Sheet: material and surface coloring. At present, most of the materials in the market can be divided into three categories: particleboard, solid wood multilayer and pure solid wood. Because they are made of different technology, so in the price and safety from high to low. The particleboard is not recommended for purchase by individuals. The glue content is too high and the formaldehyde content exceeds the standard, which has a great impact on the physical development of children.