Which component is essential for the waterproofing of a container's door?

The door gasket is essential for the waterproofing of a container's door because it serves as a sealing mechanism that closes the gap between the door and the container frame. When the door is closed, the gasket compresses and forms a tight seal, preventing water and moisture from entering the container. This feature is crucial for protecting the contents inside from external elements, ensuring that items stored in the container remain dry and secure during transport and while being stored.

In contrast, components like the door handle, door hinge, and door lock serve different functions. The handle is primarily for opening and closing the door, the hinge allows the door to pivot, and the lock secures the door against unauthorized entry. While these elements are important for the overall functionality of the container, they do not contribute to its waterproofing capabilities.