Atomic Aquatics Z2 the most compact and economical regulator system, the Z2 may be the least expensive of the Atomic line, but its combination of performance, ergonomics and materials are unmatched by the most expensive competitors. Built upon the B1/T1 platform, it shares the same breathing performance and patented features. The Z2 is a Balanced Flow-Thru Piston Design using Atomic's Jet Seat High-Flow Stainless Steel Piston. Exclusive High-Pressure Piston Seal System is Self-Lubricating for Low Friction and Low Maintenance. The Atomic Jet Seat System has No Sharp Edges that can damage the seat over time, like most competitors' first stages. Instead, Atomic employs a Conical Seat and Blunt-End Piston. Atomics' Valve Seats are Precision Machined from an Extremely Strong Aerospace Specification Seat Material. This design combination is the most Reliable Seat System in the industry and enables the seat to go 2-years or 300 dives without service. Diving Performance is Superior at even Low Tank Pressure. The Regulator is NITROX ready for Mixtures Up to 40% out-of-the-box. The First-Stage has 2 High-Pressure (HP) 7/16" and 5/7 Low-Pressure (LP) 3/8" Ports. The Z Series Second-Stage is a Balanced Linear Flow Design for Extremely Easy Breathing at all Depths and Dive Conditions. The Z Series Second-Stage is Built-to-Last with a Zirconium Plated Brass Demand Valve Body, Titanium Lever and Sealing Orifice. The Diaphragm is made from High Quality Silicone Rubber. This Pneumatically-Balanced Poppet Second-Stage has Atomic's Patented Seat Saving Dynamic Orifice which unlike most Second-Stage Orifices is a Floating Valve Design which Reduces Wear on the Second-Stage Poppet Seat when the Regulator is not pressurized adding Life to this Important Seal. The Z Seies Second-Stage Regulator is equipped with Atomic's Patented Automatic Flow Control (AFC). This Unique Diaphragm Activated Vain Automatically Controls the Flow and Venturi-Effect of the Second-Stage for Optimum Breathing Resistance at all Depths. The Second-Stage does have a Rapid Adjustment Knob for Rare Special Situations. The Regulator comes equipped with a 3/8" Threaded 32" (81.3 cm) Low Pressure Hose. The Regulator weighs 2.3 lbs (1,070 g) comes with an Owner's Manual and is MADE IN THE USA & covered by a Limited Lifetime Warranty.