Flow of air through the helmet could be controlled by manually adjusting the back-pressure on the helmet exhaust valve, usually on the lower right side of the bonnet, and by manually adjusting the inlet supply valve on the airline, usually fastened to the front lower left of the corselet. Flow rate would also be affected by the surface delivery system and depth.
Air flow through the helmet could be controlled by manually fine-tuning the back-pressure on the helmet exhaust valve, typically located on the lower right side of the hood, and by manually adjusting the inlet supply valve on the air line, which is connected to the front left side of the chest plate. Air flow rate would also be influenced by the surface delivery system and depth.