1. Contract varieties: IH, IF and IC are used to represent SSE 50, CSI 300 and CSI 500 respectively, and IO is used to represent CSI 300 stock index options.

2. Contract time: the contract time is represented by four numbers, for example, 2006 and 20 represent the year of this century, that is, 2020; 06 indicates the delivery month of the futures contract, that is, June.

3. For stock index options: the contract code is more complicated than stock index futures, such as IO20 10-C/P-4050, where C stands for call option, P stands for put option and 4050 stands for exercise price of the contract.