The Atomic Aquatics ST1 is the world's only Stainless Steel regulator and the right choice for the environment. The first stage is beautifully machined from a special grade type 316 stainless steel that is twice the strength of brass with corrosion resistance approaching titanium. Many environmental experts around the world have classified Stainless Steel as the "Green" metal of the future. It does not require any additional protective chrome or nickel plating processes that can be harmful to the environment and is 100% recyclable. The second stage features all titanium second stage components as found in the T2 and B2 regulator models.

First stage of type 316 stainless steel that is twice the strength of brass with durability and corrosion resistance nearing that of titanium.
Compact first stage features 5-port low-pressure swivel and exclusive "Jet Seat" piston design.
Exclusive, patented Atomic Aquatics "Comfort Swivel" second stage hose. The only second stage swivel of its type that allows unidirectional movement without any loss of performance. This swivel articulates at the slightest movement to eliminate any binding or pulling of the second stage hose in the mouth. Constructed of polished 316 stainless steel. 
Seat Saving Orifice: Exclusive, patented Atomic Aquatics feature prolongs the second stage seat life indefinitely, eliminating aggravating leaks and degradations in performance.
AFC: (Automatic Flow Control) Exclusive, patented Atomic Aquatics feature automatically adjusts airflow at depth to maintain stable, comfortable breathing.. 
Nitrox ready up to 40% .
2 year/300 Dive service interval: Corrosion resistant materials and maintenance saving designs extend the customary annual service period to 2 years.