Which component of the SCBA shows how much air is remaining in the cylinder?

The component of the SCBA that indicates how much air remains in the cylinder is the Heads Up Display (HUD). This device provides a visual indication of the remaining air supply to the user, typically through lights or a digital readout, allowing a firefighter to easily monitor their air supply without needing to look away from their tasks.

The HUD enhances safety by ensuring that firefighters can quickly assess their air status, enabling them to make critical decisions about their time and safety in hazardous environments. This feature is particularly beneficial in low visibility situations where checking a pressure gauge might be difficult.

While the pressure gauge also shows the air pressure in the cylinder, it requires visual inspection and does not provide the real-time, easily accessible feedback that the HUD offers. The regulator assembly is responsible for delivering air from the cylinder to the wearer but does not indicate the remaining air supply, and the control module usually refers to the overall system management or control of the SCBA.