Atomic Aquatics ST1 Regulator First stage of type 316 stainless steel that is twice the strength of brass with durability and corrosion resistance nearing that of titanium. High performance breathing: Low inhalation efforts even at deep depths and high breathing rates with natural and comfortable air delivery. All titanium second stage construction: The industry's only second stages to feature all-titanium components that are lightweight and the ultimate in corrosion resistance. 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.