What is the purpose of the firefighter's "PASS device"?

The purpose of the firefighter's "PASS device" is primarily to emit an alarm when a firefighter becomes motionless. This safety feature is critical in hazardous environments, as it alerts other firefighters and rescue personnel that a member may be in distress or incapacitated. The device is designed to activate after a period of inactivity, typically around 30 seconds, and emits a loud alarm to ensure that the individual is located and assistance can be provided promptly. This contributes significantly to the overall safety and accountability of firefighters operating in dangerous and potentially life-threatening situations.

The other options relate to important aspects of firefighting but do not accurately describe the specific role of the PASS device in ensuring the safety of firefighters. Communication, air supply monitoring, and visibility enhancement are vital components of firefighting operations, but they fall outside the specific function of the PASS device.