The so-called box refers to the fact that the index and index form a certain area during the operation, that is, they fluctuate within a certain range to form an operation box. When the trend slides to the bottom of the box, it will be supported, and when the stock price rises to the top of the box, it will be under pressure from the top. The movement only runs within the scope of the box, which is called box operation. The horizontal disk can be understood as the movement of the box. Mostly used in the trend of financial indexes such as stocks, futures and funds.