Which feature must be present with the fire extinguisher according to pre-trip inspection requirements?

A functioning safety pin is a critical feature that must be present with the fire extinguisher during a pre-trip inspection. The safety pin is designed to prevent accidental discharge of the extinguisher. It must be intact and securely in place to ensure that the extinguisher remains operable until it is needed. If this pin is missing or not functioning properly, the extinguisher could fail to operate correctly in an emergency, putting the driver and others at risk.

In contrast, a visible sticker that is expired does not satisfy safety requirements and does not reflect the operational status of the extinguisher. A manufacturer label in another language might not meet regulatory standards, as labels often need to be in English for clear understanding. Similarly, while a heavy metal case could offer protection for the extinguisher, it is not a mandatory feature according to pre-trip inspection requirements. Thus, having a functioning safety pin directly impacts the effectiveness and reliability of the fire extinguisher, making it a necessary feature for safety compliance.