The external market is also called active buying, that is, the cumulative transaction volume of the transaction price at the selling price; Active selling in the market, that is, the cumulative volume of transactions at the purchase price. The outer disk reflects the buyer's wishes and the inner disk reflects the seller's wishes.

The two data of inner disk and outer disk can be used to judge the strength of buying and selling rights. If the number of external disks is greater than the number of internal disks, the buyer is stronger; If the number of inner disks is greater than the number of outer disks, the strength of the seller will be stronger. Through the size and proportion of the number of external and internal markets, investors can usually find out whether they are actively buying or actively selling. In many cases, they can find the trend of bookmakers, which is a more effective short-term indicator. However, investors should pay attention to the transaction of stock prices at low, medium and high levels and the total turnover of stocks when using external and internal markets. Because the number of outer disk and inner disk is not always effective, many times the price does not necessarily rise because of the large outer disk; The internal market is large, and the price may not necessarily fall.