What component is not typically listed with an SCBA's face piece, backplate, and air cylinder?

The choice of a regulator as a component not typically listed with a Self-Contained Breathing Apparatus (SCBA) setup that includes the face piece, backplate, and air cylinder is insightful. The main components of an SCBA system generally focus on the parts directly associated with storing and delivering breathable air.

The face piece is the mask that the user wears to ensure that they receive filtered and safe air, while the backplate provides structural support for the air cylinder. The air cylinder contains the compressed air that the user breathes. While the regulator is indeed an essential part of the SCBA system, it is often considered an accessory component that manages the flow of air from the cylinder to the wearer, rather than a primary component like the face piece, backplate, and air cylinder themselves.

In many contexts, the primary focus is on the components that directly comprise the primary structure of SCBA, leading to the regulator being excluded from this specific listing. This distinction helps clarify the roles of different parts within the overall SCBA system, emphasizing that the most fundamental elements do not always include the regulating mechanisms, which, while crucial for operation, support the more fundamental components.