Which of the following tools is used for communication between firefighters?

The tool used for communication between firefighters is the mobile radio, which allows for instant and effective communication during operations. This is crucial in emergency situations where coordination and real-time updates can significantly impact the safety and efficiency of a response.

Mobile radios facilitate communication over distances and through various obstacles, enabling firefighters to relay information about their environment, request assistance, and share updates on the status of operations. This tool enhances teamwork and situational awareness, ensuring that all personnel are informed and can act accordingly.

In contrast, the other tools listed do not serve a communication function. A hydrant wrench is specifically designed for operating fire hydrants, a rubber mallet is often used for tapping and adjusting equipment or securing connections, and a Halligan bar is a forcible entry tool used to gain access into buildings. While these tools are essential in firefighting operations, they do not aid in communication.