Futures trading volume refers to the bilateral cumulative quantity of a futures contract traded on the same day, and the unit is "hand". VOL is a volume indicator. Mainly depends on the volume of K-line. The longer the lower column, the greater the transaction volume and the more active the transaction. On the contrary, the smaller. Next to the volume indicator, there will be a numerical value showing the specific volume of the K line. Combined with OI index, we can see whether the K-line is open or closed.