High-performance regulator with over-balanced diaphragm first stage and pneumatically balanced second stage for smooth breathing and reliable depth performance.

First Stage

• DS4 over-balanced diaphragm: Medium pressure gas increases at a rate faster than ambient as depth increases to maintain superior performance at depth.
• Ports: 2 high-pressure (HP) ports and 4 medium-pressure (MP) ports, angled for optimal hose routing.
• Environmental dry system: Keeps water out of the main spring chamber to prevent ice buildup and reduce silt and contamination ingress.

Second Stage

• Pneumatically balanced: Smooth, easy breathing performance.
• XTX two-stage progressive purge: Side press for lower flow (more control, e.g., filling lift bags); center press for full purge (clearing the regulator).
• Large venturi lever: Soft-touch rubber grip for easy location and use; reduces grit ingress to maintain smooth operation.
• Opening effort control knob: Easy-to-grip knob to adjust inhalation effort.
• Antimicrobial molded parts: Active additive provides protection against MRSA, E. coli, bacteria, fungi, viruses, mould, yeast, and algae.
• Silicone exhaust valve: Improves breathing performance.
• Comfo-bite™ mouthpiece: Designed to minimize jaw fatigue.
• Patented heat exchanger: Surrounds the valve mechanism to dissipate cold from gas expansion and draw in ambient water warmth.