What should be checked on a carabiner to ensure its proper function?

To ensure the proper function of a carabiner, it's crucial to check if the gate locks smoothly. This is essential because a properly functioning gate is vital for the safety and reliability of the carabiner during any rope rescue operations. If the gate does not lock smoothly, it may fail to secure the load it is meant to hold, posing a significant risk during rescue scenarios.

Checking for rust on the surface can indicate wear and degradation, which affects the carabiner’s strength and durability. However, the functionality of the gate mechanism directly impacts the operational safety of the equipment. While brand and color might influence preferences or visibility, they have no bearing on the carabiner’s performance and safety features. Thus, ensuring the gate locks smoothly is the most critical aspect to verify for the proper function of a carabiner.