If he wants to make other varieties, he must enter other trading pools. The settlement of early futures trading is very slow and complicated (without computer assistance), so the workload is very heavy. Therefore, the fees (membership fees or seat fees) charged by the futures exchange for members who trade all varieties and members who only trade some varieties are different. The membership fee for trading various products is the highest, because there are many kinds of transactions, so the settlement is complicated.
But the charge for trading only one or a few varieties is less. In addition, some traders only need to trade one or a few varieties (for example, a soybean producer may only need to trade soybeans, and he may not be interested in corn and wheat on the same exchange at all).
Therefore, the Exchange divides members who participate in transactions into full members who participate in various transactions and general members who only participate in certain transactions. Full members can enter any trading pool for trading, and ordinary members can only trade in the trading pool in which they have the right to participate.
In addition, they are also members of the exchange. Some members have settlement authority (they can directly settle accounts with the exchange and settle accounts for others), while others have no settlement authority (they cannot directly settle accounts with the exchange and need others to settle accounts for them).
Those who have all business rights in the exchange are called "full members", and those who have only some business rights are called (ordinary members).