Diver adjustable inhalation effort Most downstream demand valve regulators are calibrated during manufacturing to a single, 'middle of the road' operation. Whether finning up current at 100+ feet or merely snorkeling out to the dive site, this factory adjustment may not be optimum for the wide variety of demands we place on our equipment. A simple twist of the Delta 4's adjustment knob enables complete control...set the inhalation requirement to near zero when you need ultimate performance, or tune it for greater resistance as conditions or preferences change. Patented Dynamic Adjustment A common objection to adjustable second stages is that divers can't imagine themselves twisting and turning a knob as they descend and ascend through the depths. If inhalation resistance is set near zero at depth, your ascent would require you to manually increase resistance as ambient water pressure is reduced to prevent free-flow. Taking another stride beyond common second stage engineering, Oceanic designed a patented DYNAMIC ADJUSTMENT feature into the heart of the Delta 4. This mechanically balanced valve maintains a preferred breathing resistance throughout the dive. Set it once and the Delta 4 automatically adjusts to make breathing as easy at 100 feet as it is at 30 feet - with no additional manual adjustment. Adjustable Venturi System (A.V.S.) The A.V.S. deflector vane found in the Delta 4 diverts the airflow from the valve directly to the mouthpiece, producing smooth venturi-assisted inhalation. With the addition of a user Adjustable Venturi System (A.V.S.), in the form of a simple yet ingenious switch, full adjustment control rests in the hands of the diver. In-Line Swivel The Delta 4 features an ergonomically designed in-line swivel for ultimate comfort. Improved Adjustment Mechanisms Both the Dynamic Adjustment Knob and A.V.S. Switch are designed to be unobtrusive, yet easily manipulated even with the thickest gloves. Surge Deflector Our surge protector (the titanium, blue or yellow that you see in the images above) reduces freeflow caused by surge or oncoming current. Computer optimized design Oceanic regulators are exclusively designed using the latest 3-D computer modeling techniques. This allows us the ability to model and test performance while still in the early stages of development. The Delta 4's unique deflector vane and housing design diverts airflow from the valve directly to the mouthpiece, producing smooth venturi-assisted inhalation. Lightweight The Delta 4's housing is made from an ABS/Polycarbonate composite blend of materials making the Delta 4 both extremely rugged and lightweight (6.7 ounces) and nearly neutrally buoyant underwater, reducing jaw fatigue on extended dives. The extremely ligweight cover ring is machined from a solid piece of aircraft aluminum, and then hard anodized, utilizing a unique process to prevent corrosion. Patented Orthodontic Mouthpiece To further reduce jaw fatigue, the Delta 4 features a patented Orthodontic Mouthpiece, designed to accommodate the natural overbite of the human jaw. Nitrox Compatibility The Delta 4 is classified as being suitable for use with nitrox breathing gas mixtures containing up to 40% oxygen by volume without the need for special preparation, cleaning or component parts. CDX-5 Compact Balanced Diaphragm First Stage The CDX-5 Balanced Diaphragm First Stage is the perfect regulator for extreme diving conditions, such as ice diving or diving in high sediment. The balanced diaphragm first stage design has been the regulator of choice for many divers who find themselves pushing the envelope. The advanced design of the CDX-5 isolates the critical seats and o-rings from the harsh environment. This helps prevent internal corrosion and contaminant buildup, leading to more consistent performance between service intervals.