Perm is a patented product of Shandong Hailong, which is a chemical fiber made of jute. Hebei Qiu Ji Chemical Fiber Company also produces it. Their product is called aso fiber. Modal is a patented product of Austrian Blue Crystal Company, which is a high-performance chemical fiber made of wood fiber, and bamboo fiber is a chemical fiber made of bamboo, which is produced by several chemical fiber factories in China. They are all chemical fibers in essence, also called viscose fiber, regenerated fiber and cellulose fiber. Functionally, modal fiber is soft, with high fineness, better spinnability than ordinary viscose fiber and the highest price. Bamboo fiber and perm fiber have similar properties, but their spinnability is poor, so they usually need to be blended with cotton or other fibers to have more economic value.