Hair belly is the cow stomach, alias: louver belly, belly tip, cow stomach, hair belly, is one of the internal organs of cows, that is, the third stomach (the ovum) in the stomach of the cow. The page-like pleats are composed of large and small leaves and bottom plates, so the most commonly used name for hair belly is louver belly. Lao Pai Mao Du is made of louver belly as raw material. It adopts many fine processes such as cleaning, tearing, cutting, and pickling. Finally, it is soaked in water with onion, ginger, and pepper juice.