What is the function of a customs catch?

The function of a customs catch is to prevent the inner door from opening when the outer door is closed. This is essential for maintaining the security of the cargo within the container. By ensuring that the inner door remains closed, the customs catch helps prevent unauthorized access to the contents during transport and storage. This feature is particularly important in international shipping, where cargo must remain secure and tamper-proof during transit to comply with customs regulations and to protect the integrity of the shipping process.

The other options do not accurately describe the role of a customs catch. The mechanism is not designed to enhance the locking of doors or improve ventilation, nor is it intended to secure additional cargo inside. Its primary purpose remains focused on securing the inner door, thereby ensuring that the cargo is protected throughout its journey.