The futures contract of each commodity stipulates a unified and standardized quantity and unit of quantity, which are collectively called "trading units". For example, Dalian Commodity Exchange stipulates that the trading unit of soybean futures contract is 10 ton. That is to say, when you buy and sell soybean futures contracts on Dalian Commodity Exchange, you should start with 10 ton, which is 1 lot as far as the futures market is concerned, and it is the smallest trading unit. You can't buy 5 tons or sell 8 tons of soybeans in the futures market.