PU (Polyurethane) is one of the few materials that can have the properties of plastic and rubber. With the development of technology, PU has developed from the low-grade playground track, foam and even artificial leather to modern and can produce soft lining. The material of the leather surface which is integrally formed and coated has good skin-friendliness, durability, rebound speed and soft and hard material adjustable formula, and is frequently used in high-end sports equipment in advanced countries in Europe and America.