This is the Oceanic Delta 5 + EDX Scuba Diving Regulator 1st & 2nd Stage Features: Pneumatically balanced all-metal valve. Dive/pre-dive switch & patented dynamic airflow adjustment control. Mechanical Purge button for consistent air-flow pressure on during purge. Nitrox Compatibility - Standard to 40%. Balanced diaphragm first stage eDX is environmentally sealed and cold-water ready. Heat Exchanger for Improved cold-water performance. Ergonomic exhalation venting. Dimensions (Front Profile) - 2.5 inch diameter (circular). Dual-material orthodontic mouthpiece with bite tabs. Service Interval - 2 Year, Required. Lifetime Warranty with Free Parts for Life. 30 day satisfaction guarantee. Miflex Braided Hose - Standard. Optional Universal Swivel Adapter - the optional Universal Swivel comes separate but can be easily installed with an adjustable torque wrench and 5 min of free time. Instructions are provided. The Delta5 is the next step in a long line of remarkably reliable, durable and smoothly breathing regulators to carry that name. Sure, we&';ve given it an updated look, but that&';s not all. Like the Delta&';s before it, the 5 comes standard with our patented Dynamic Adjustment Technology that, once set by the diver, provides consistent airflow at any depth. They also come standard with a dive/pre-dive switch and a super comfortable orthodontic mouthpiece. This latest edition though has a new, and updated, all metal pneumatic valve providing super smooth breathing performance in any condition. We have also added a heat exchanger, positioned on the hose connection to the 2nd stage, to further increase it&';s already stellar cold water performance. We&';ve paired the Delta5 with the new eDX. This top-of-the-line cold forged, over-balanced diaphragm first stage is environmentally sealed and comes with 4 low-pressure and 2 high-pressure ports. It also comes equipped with a heat exchanger for added cold water performance.