Atomic Aquatics Z2 Regulator First Stage: First 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 cap Second Stage: Second stage components are made of precision machined Brass with Zirconium plating and Titanium Patented Atomic Seat Saving Orifice (Titanium) Patented Atomic Automatic Flow Control (AFC) Rapid adjustment knob for manual second stage de-tuning in special situations A new high-flow second stage case that significantly lowers breathing effort at any depth from shallow water to beyond the limits Dual material second stage cover enables entire front to be used for purge Dual silicone comfort fit mouthpiece with tear-resistant bite tabs 2 year/300 dive service interval Limited Lifetime Warranty not contingent on proof of service