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Tusa RS-790 Regulator - First and Second Stage Set - DIN

RS-790 DIN


This Tusa RS-790 Regulator Set includes the R-700 DIN first stage and S-90 second stage. The Tusa RS-790 Regulator Set is directly comparable to the Scubapro MK17 first stage with a S550 second stage that is so popular with technical divers around the world - same port configurations and equivalent performance.

Like many companies, Tusa packages their regulators according to a code system that denotes both the first and second stages. In this case, the first stage is the Tusa R-700, a balanced diaphragm design with a dry pressure chamber and an exterior rib section. The latter features are specifically designed to improve performance under cold water conditions. The dry chamber also reduces the risk of corrosion for the reg’s internal moving parts. The first stage also comes equipped with two HP and four LP ports. Two of those LP ports are designated as "high flow" ports, delivering 15% more air than the normal LP port. This is a handy feature for divers with LP accessories that are a little hungrier for air.

The all chrome plated marine brass first stage regulator is a balanced diaphragm design which is environmentally sealed. The diaphragm membrane transmits the pressure changes to the internal mechanism eliminating the need for the surrounding water to enter the intricate mechanism. The benefit of this type of first stage design is that none of the internal parts are exposed to contaminants such as salt, sand, chlorine or pool acids. These environmental contaminants cause corrosion and mineral deposits to form on the internal mechanism deteriorating regulator performance.

TUSA has taken this concept one step further with the addition of a Dry Ambient Pressure Chamber. A standard diaphragm first stage regulator allows some water to enter the main spring cavity. Although the cavity is not associated with the intricate internal components, it does allow the cold water to rest against the primary diaphragm cooling the air that passes through the first stage. This colder air can promote second stage freeze up when diving in cold water. The Dry Air Ambient Chamber prevents water contact with the diaphragm and spring maximizing performance, at any depth, in cold water conditions below 50 degrees Fahrenheit (10 degrees C). In addition the outside of this chamber is ribbed increasing the parts surface area thus acting like a radiator to increase heat transfer further reducing the problems associated with cold water diving.

The first stage has two high flow low pressure ports (LP) and two standard LP ports along with two high pressure ports (HP). The high flow LP ports are positioned near the diaphragm and offer up to a 15% increase in air flow.

The other half of the Tusa RS-790 Regulator Set is the S-90 second stage, a pneumatically balanced design. It comes with a venturi knob, but as an added plus that knob is labelled. No more guesswork for infrequent divers who can’t remember which way to turn their knob!

Being a pneumatically balanced system the Tusa S-90 second stage has a small chamber positioned at the end of the poppet assembly that traps air and forces the poppet back against the intermediate pressure orifice. This provides decreased inhalation resistance and increases smooth breathing in all conditions. The lightweight compact composite designed second stage is also equipped with a Venturi Adjustment Lever. This lever has two positions that are selectable by the diver. Use "Surface" or 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. The second stage comes standard with an orthodontic-conscious designed silicone mouthpiece.

The Tusa RS-790 Regulator Set is Nitrox compatible to 40%, comes with a comprehensive Owner's Manual and is covered by TUSA's limited lifetime warranty.

Tusa RS-790 Regulator DIN Features

  • Tusa R-700 DIN 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
  • Tusa S-90 Second Stage:
    • Pneumatically Balanced Design
    • Lightweight, Compact Composite Case
    • Venturi Adjustment Lever
    • Ortho-Consciously Designed Silicone Mouthpiece
  • Owner's Manual
  • Limited Lifetime Warranty

Yoke version available as RS-790 YOKE

Drop Ship
This is not a regularly stocked item in our Rye dive shop. It will be ordered for you from the manufacturer upon request and typically shipped direct from them to you the same day thus resulting in no delay in delivery.

(08/18 LRB)

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The Scuba Doctor Australia
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