Breathing underwater should feel natural, and that experience is one of the things that most clearly separates Halcyon second stages from our competitors. As soon as you experience the smooth, high volume of air delivered by a Halcyon second stage, you will be hooked. Our high quality second stage regulators provide diver adjustable controls for the ultimate in breathing performance. Halcyons Halo second stage offers steadfast reliabilit and impeccable performance. Two methods of breathing adjustment make it the top choice for demanding Halcyon divers. Balanced, downstream valve offers incredibly smooth breathing in all conditions. The design slightly offsets the force of the downstream air entering from the first stage, allowing reduced spring tension and a decreased inhalation resistance. Halcyon first stages are balanced, so the Halo is a perfect fit with either the H-75P or H-50D Halcyon first stage. Adjustable inhalation control refines breathing effort by way of an easy access c