The RS-790 delivers performance, durability and comfort making it the ideal choice for discerning divers. The R-700 is a balanced diaphragm first stage designed for cold-water use, it features a dry ambient pressure chamber that prevents water contact with the diaphragm maximizing performance in temperate water conditions below 50°F/10°C. Additionally, the R-700 has an external rib section that nearly doubles the surface area for thermal exchange further reducing ice formaton that can lead to freeze up in extreme conditions. The R-700 has two high pressure ports and four low pressure ports including two high flow (HF) that deliver up to a 15% increase in air flow. It is available in both INT (yoke) and DIN versions. The S-90 second stage is a compact pneumatically balanced system that features a composite housing which insulates and protects under extreme cold-water conditions. The S-90 is equipped with a built-in venturi adjustment lever allowing the diver to select a surface or minimum setting reducing possible free flow or a dive setting for maximum air flow during the dive.