Which of the following is a main component of the MSA G1 SCBA?

The air cylinder is indeed a main component of the MSA G1 SCBA. It serves as the primary storage for the breathable air that the user relies on while operating in environments where the air is not safe to breathe. The air cylinder is typically made from lightweight materials to enhance the portability of the SCBA and is designed to withstand high pressure, allowing it to store a sufficient volume of air for various operational durations.

Oxygen source, while vital for breathing, is indirectly referenced through the air supplied from the air cylinder rather than being a separate or distinct component in the SCBA system. A cooling system is not a standard component of SCBA units, as these systems primarily focus on air supply and safety measures rather than temperature regulation. Similarly, a flame suppressor is not part of the SCBA design, as the SCBA is focused on providing breathable air, not directly combating flames. This positions the air cylinder as a critical and fundamental part of the SCBA's functionality.