What is a common feature of SCBA masks?

A common feature of SCBA masks is that they provide a full face seal to protect personal safety. The design of these masks ensures that they create a tight-fitting barrier around the entire face, which is essential in preventing the inhalation of hazardous airborne contaminants. This seal is crucial for maintaining an effective respiratory protection system, as it helps to ensure that the air the user breathes is clean and free from toxins, smoke, or other harmful agents present in environments like firefighting or industrial settings.

While some SCBA masks may have features like tinted lenses or built-in communication systems, these are not standard across all models and do not specifically ensure the primary function of protecting the user's respiratory system. Similarly, heads-up displays for air supply levels are advanced features found in certain high-end models but are not universally included in all SCBA designs. Therefore, the full face seal is indeed the defining characteristic that underscores the primary function of SCBA masks, which is to provide a safe and breathable atmosphere in dangerous conditions.