What tool is commonly carried by fire fighters to tighten and loosen hose fittings?

The tool commonly carried by firefighters to tighten and loosen hose fittings is the spanner. Spanners are specifically designed to fit the couplings and fittings used in firefighting hoses. This tool allows firefighters to quickly and securely connect and disconnect hoses during operations, ensuring that water flow can be established and maintained efficiently during emergencies.

The design of a spanner typically includes a pair of jaws that can accommodate different sizes of hose fittings, providing versatility in various situations. Its robust construction allows it to handle the mechanical stresses encountered during firefighting tasks, making it an essential piece of equipment for ensuring effective operation.

While other tools like wrenches and socket tools serve important functions in various mechanical applications, they are not specifically tailored for hose fittings. A pry bar, on the other hand, is not relevant for any hose connection tasks. Thus, the spanner stands out as the appropriate tool for firefighters in managing hose fittings securely and effectively.