Felt is a kind of wool sheet which is heated by loosening, carding, auxiliary netting, shrinking and roll-to-roll to make the scales of wool open. It combines the top and bottom of the wool sheet to form a warpless and weft-free felt. According to the density requirement, it achieves the strength of crossing. After drying and flattening, it can make the felt smooth, uniform and even. Delicate, no hair loss, wrinkle-proof, folded flat can be used. It can be washed with water. Felt is a product. It can be cut into insoles and used after purchasing new felt. It can be spread on the bed to prevent dampness and cold. If there is no waste, please discard it to the garbage site. Professional sanitation workers can recycle and burn it.