What is the correct order of the parts of a regulator?

The correct order of the parts of a regulator starts with the first stage, which attaches directly to the tank and reduces high tank pressure to an intermediate pressure. Following that, the second stage is where the diver breathes from, as it is designed to further reduce the pressure for comfortable inhalation.

After the second stage, the alternate air source second stage is typically included, which serves as a backup in case of an emergency or if a buddy needs air. It is positioned after the main second stage since it is not used as frequently. Next is the low-pressure inflator hose, which connects to the buoyancy control device (BCD) to allow the diver to manage buoyancy. Lastly, the instrument console, which presents crucial data like air pressure and depth, is usually positioned for easy visibility and accessibility.

This sequence reflects the logical flow from the high-pressure source (the tank) to the diver's breathing apparatus and support systems, highlighting the function and arrangement necessary for safe and effective diving.