The raw material of felt is pure natural wool. The most direct way to identify the wool is to rub the wool from the felt and ignite with fire. The wool is smoked and bubbling during the combustion process. The burning object has the taste of burning hair. After burning, the ashes are black embrittlement and no focus. From the surface, pure felt feels soft and elastic, and its texture is fine and regular. In contrast, chemical fiber felt is made of wool and chemical fiber, and its price is lower than that of pure felt. Its properties are characterized by pure felt insulation and softness. Chemical fiber felt can also be used to distinguish the weight of raw materials from burning smell and ashes.