When used as a safe second, Aqua Lung's Air Source 3 inflator reg breathes smoother than many primary regs. And when used as a power inflator, it delivers total ascent control. The Airsource 3 uses a screw-down fitting similar to the one used on a primary reg's second stage. This permanent connection allows for better airflow and breathing performance, plus it prevents sand, salt and corrosive moisture from getting into the second stage mechanism. An optional adaptor rings let you mount the Airsource 3 on all major BC brands.