Pun means that you need to go through two layers of approval procedures in the process of handling before you can reach the final approval stage. This review process is usually applicable to the examination and approval of national security, confidentiality and important confidential documents.

The application of pun can effectively protect state secrets, prevent leaks and improve the efficiency of examination and approval of confidential documents. This method avoids some unnecessary decision-making mistakes and ensures the correctness of the final decision.

However, double-gap doors also have their limitations. The implementation of this audit process requires a certain amount of time, manpower and material resources, which may lead to some unexpected events that cannot be handled in time. At the same time, the application of "double clearing" may also delay some important decisions, thus affecting the country's strategic decision-making and development. Therefore, in practical application, it is necessary to reasonably grasp the application opportunity and scope of the double-clearing door, so as to make it really play a role.