The Zeagle Onyx II Regulator outperforms many, much more expensive regulators with outstanding reputations - why? The internal structure allows direct airflow through the 1st stage, providing lower-turbulence for outstanding performance. Zeagle's conical precision stainless steel high-pressure valve and advanced polymer seat provide much greater reliability and service life compared to conventional designs, while improving responsiveness and Performance at all Breathing Rates. Zeagle's regulators are US made, built under strict controls for quality in Zeagle's own factory, using state of the art equipment and procedures. Your regulator is one of your most important pieces of gear. No matter what kind of diving you do, you can do it better with Zeagle. The black chrome plated marine brass first stage regulator is a balanced diaphragm design which is Inherently environmentally sealed. The diaphragm membrane transmits the pressure changes to the internal mechanism eliminating the need for the surrounding water to enter the intricate mechanism. The benefit of this type of first stage design is that none of the internal parts are exposed to contaminants such as salt, sand, chlorine or pool acids. These environmental contaminants cause corrosion and mineral deposits to form on the internal mechanism deteriorating regulator performance. First Stage is equipped with 2 high pressure (HP) 7/16" threaded ports and 5 low pressure (LP) 3/8" threaded ports for mounting of gauges and additional accessory items such as inflator Hose and octopus regulator. With high performance porting in a balanced diaphragm design with environmentally and dry seal installed, make this one clean regulator first stage that will give you years of corrosion free service and extreme reliability in cold water conditions. Zeagle's Onyx Second Stage is lightweight, compact and comfortable, with diver adjustable inhalation resistance controls, free-flow control, and anodized aluminum heat sink built-in anti-freezing feature. Specific design changes have created a regulator that is resistant to free-flow on the surface, yet has incredible smoothness and ease of breathing underwater. This pneumatically balance downstream demand valve second stage regulator is manufactured from flexible and ridged thermoplastic, elastomeric, polymer and silicone rubber. The complete regulator weighs 42.6 oz (1,208 g) with the hose comes with a comprehensive owner's manual, is is Nitrox ready to 40% out of the box and is covered by Zeagle's limited lifetime warranty.