Futures primary refers to the smallest trading unit of futures contracts. In different futures markets, different futures varieties, the number of primary transactions may be different. The number of first-hand transactions is usually the standard unit stipulated by the exchange, also known as the contract unit. Investors need to buy or sell at least one contract when trading futures. If they want to trade a larger quantity, they can buy or sell multiple contracts, such as two hands and three hands. In the course of trading, the expenses that investors get or need to pay, such as margin and handling fee, are also calculated on the basis of each contract.