What are the big black circles below the inhalation valves on the mask known as?

The big black circles located below the inhalation valves on the SCBA mask are known as voice emitters. Voice emitters are an important feature of breathing apparatus masks, as they allow the wearer to communicate more effectively while using the SCBA. They enable sound to transmit through the mask, allowing spoken words to be heard clearly even in noisy environments, which is crucial for safety and coordination during firefighting or rescue operations.

Voice emitters are designed to minimize the obstruction that the mask may create when trying to communicate. This feature enhances situational awareness and teamwork, which are vital in emergency scenarios. Understanding the role of voice emitters can help users appreciate how communication plays a critical role in the effectiveness of their operations while using SCBA equipment.