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.
The RS-790 offers the following features:
R-700 First Stage
Dry Ambient Pressure Chamber
The dry ambient pressure chamber on the R-700 prevents water contact with the diaphragm and spring maximizing performance, at any depth, in cold water conditions below 50°F/10°C.
Ideal For Cold Water Environments
The R-700 is engineered for cold water diving. It features a ribbed top cap section that acts like a radiator to increase the surface area for heat transfer. This design allows warming of the critical internal first stage parts that can freeze due to the gas pressure drops and low temperatures.
High Flow Ports
Two high flow low pressure ports are available on the R-700 in addition to two standard LP ports and 2 HP ports. The high flow ports are positioned near the diaphragm and offer up to a 15% increase in air flow.
S-90 Second Stage
Pneumatically Balanced System
The S-90 second stage is a pneumatically balanced design. A small chamber positioned at the end of the poppet assembly traps air and forces the poppet back against the intermediate pressure orifice. This provides decreased inhalation resistance and increases smooth breathing in all conditions.
Venturi Adjustment Lever
The S-90 is equipped with a built-in Venturi adjustment lever. Two positions are selectable by the diver. Use Surface or the minimum setting when entering the water or on the surface, reducing the sensitivity and possible free flow of the second stage. Use the Dive or maximum setting for maximum air flow during the dive.
- First Stage:
- Balanced Diaphragm Design
- Anti-Freeze System
- Dry Ambient Pressure Chamber
- Ideal for Temperatures Below 50 Degrees Fahrenheit (10 Degrees Celsius)
- Nitrox Compatible to 40%
- Environmentally Sealed
- 2 High Flow LP Ports 15% Increase Air Flow
- 2 Standard LP Ports
- 2 HP Ports
- Second Stage:
- Pneumatically Balanced Design
- Lightweight, Compact Composite Case
- Venturi Adjustment Lever
- Ortho-Consciously Designed Silicone Mouthpiece
- Owner’s Manual
- Limited Lifetime Warranty