Check the listing for details. Atomic Aquatics Z3 1st Stage Regulator - Din/Yoke or Sealed/Open. Condition: New. Listed at 434.95 USD. The “Z” designation is represented by the use of Zirconium as plating material for the precision machined Brass valve body. Atomic developed a Zirconium over Chrome over Brass plating process to deliver corrosion-resistance 3-4 times that of conventional chrome plating.First stage materials are chrome plated Brass and 316 Stainless SteelAtomic Jet Seat high-flow piston first stageOptional factory-sealed first stage to prevent outside contamination such as silt and sandNitrox ready for mixtures up to 40%First stage ports available in 2 HP fixed / 7 LP on fixed capFirst stage materials are chrome plated Brass and 316 Stainless Steel Atomic Jet Seat high-flow piston first stage Optional factory-sealed first stage to prevent outside contamination such as silt and sand Nitrox ready for mixtures up to 40% First stage ports available in 2 HP fixed / 7 LP on fixed capFirst stage materials are chrome plated Brass and 316 Stainless SteelAtomic Jet Seat high-flow piston first stageOptional factory-sealed first stage to prevent outside contamination such as silt and sandNitrox ready for mixtures up to 40% The combination of performance, ergonomics, features and materials found in the Z2 adds up to a cost efficient regulator option, without compromising performance or durability. The chrome plated brass first stage comes with a fixed 7 port cap and 2 high pressure ports. The second stage houses corrosion resistant zirconium coated brass and titanium components. Environmental sealing is optional.