This balanced, environmentally sealed diaphragm design provides superb performance especially in cold water with consistent performance at varying tank pressures and depths. You will experience smooth, easy breathing throughout your dive. The dry, balance chamber, diaphragm design prevents the entry of water into the first stage mechanism and enhances a trouble-free operation; this is true even in the toughest conditions.
Two opposing high pressure ports allow you to choose where to route your SPG.  Four stationary low pressure ports allow you to customize your hose routing for comfort and convenience. The H50-D features high flow high flow LP port options, providing the best air delivery with up to 15% more gas than other LP ports.

Features :
-Balanced, environmentally sealed diaphragm
-Dry balance chamber ensures solid performance in the worst conditions
-Two high pressure ports, four intermediate/low pressure ports
-300 bar DIN connection, compatible with 40% Nitrox
-Externally adjustable intermediate pressure (IP)

The Halo.

This high quality second stage regulator provides diver adjustable controls for the ultimate in breathing performance.  Halcyon’s Halo second stage offers steadfast reliability, and impeccable performance. Two methods of breathing adjustment make it the top choice for demanding divers. Halcyon first stages are balanced, so the Halo is a perfect fit with either the Halcyon H-75P or Halcyon H-50D first stage.

- Adjustable inhalation control refines breathing effort by way of an easy access control knob; this allows the demanding diver an opportunity to fine-tune the air delivery of the second stage.
- Air Control Vane (ACV) offers a second diver adjustment for the ability to fine-tune breathing. The ACV uses vacuum assist technology to reduce work of breathing and increase diver comfort. This level of refinement is available on all Halcyon second stages.
- ACV in “dive” position gives powerful breathing support while ACV in “Halcyon” position helps prevent free flows; this can be helpful on the surface, when diving in currents, while scootering, or when the Halo is used as a backup regulator.
- Comfort mouthpiece is standard on every second stage to reduce jaw fatigue and mouth irritation. This long lasting mouthpiece requires only a minimum effort to hold comfortably in place.
- In combination with the freedom of head movement provided by Halcyon’s primary long hose, you will enjoy dives free from the jaw fatigue found with certain mouthpieces and/or poorly balanced hose routing.

The Aura

Aura second stage regulators provide a simple, compact design that makes breathing under water feel completely natural. This high quality second stage delivers air in a smooth, dependable fashion. Halcyon’s Aura second stage comes with a single adjustment control and a pre-set inhalation effort that suits most common diving situations. This feature makes it a common selection as a backup regulator. The Aura is an ideal regulator for divers who want a simple, ready-to-dive regulator. It is also a common choice for training systems and rental units.

Air Control Vane (ACV) offers a second diver adjustment, for the ability to fine-tune breathing. The ACV uses vacuum-assist technology to reduce work of breathing and increase diver comfort. This level of refinement is available on all Halcyon second stages.
ACV in “dive” position gives powerful breathing support, while ACV in “Halcyon” position helps prevent free flows. This can be helpful on the surface, when diving in currents, while scootering, or when the Aura is used as a backup regulator.
Comfort mouthpiece is standard on every second stage, to reduce jaw fatigue and mouth irritation. This long lasting mouthpiece requires only a minimum effort to hold comfortably in place. In combination with the freedom of head movement, provided by Halcyon’s primary long hose, you will enjoy dives free from the jaw fatigue common with certain mouthpieces and/or poorly balanced hose routing.
Comes standard with 100cm/ 40" hose.

Classic downstream valve style regulators have an impressive safety record, and are commonly accepted as an extremely reliable design. Part of their reliability is because the downstream valve opens in the same direction as the incoming airflow, and a spring counteracts the force of the incoming air. In this design, a small inhalation is required to overcome the spring tension and open the valve. This spring pressure is adjusted at the factory, and allows easy breathing and consistent performance. Your Authorized Halcyon Service Technician can make any desired adjustments.