Hair structure: Each hair consists of a cuticle layer, cortex layer, and medulla layer. The cuticle layer is the outermost layer of hair and usually consists of 2 to 4 layers of cuticle. The cuticle layer is usually translucent or colorless, so it can let out natural hair color; the cortex layer accounts for 80% of the hair, where natural pigments are deposited, the natural hair color is due to it; the medullary layer is located on the head In the center, it is composed of many small bubbles. Classification of wigs: artificial wig, fiber, high-temperature silk, real human hair, over-acid wig, complete cuticle aligned hair.