The Halcyon Halo Second Stage Regulator delivers precision breathing control with its adjustable inhalation resistance and Air Control Vane (ACV), letting you customize performance to match your diving style. Rated for 40% Nitrox, this reliable regulator integrates seamlessly with Halcyon's H-75P or H-50D first stages. Built for divers who demand superior comfort and dependable performance in demanding underwater environments.