Apeks XTX40 Dive Regulator w/ DS4

Follow the interval in your regulator's manual, since manufacturers commonly specify an annual inspection or a set number of dives and many warranties depend on it. A regulator is life-support equipment, so service belongs with a factory-trained technician rather than being attempted at home. Have it looked at sooner than scheduled if you notice increased breathing effort, free-flow, bubbles, or water in the second stage.

Make sure the dust cap is dry and firmly seated over the first-stage inlet before the regulator goes anywhere near water, because water inside the first stage is the leading cause of internal corrosion. Rinse in fresh water without pressing the purge button, since purging while depressurized can draw water back into the second stage. Shake out the water and hang it to dry with the hoses in wide, gentle loops rather than tight bends.

Regulators travel well and are usually best carried in hand luggage where they will not be crushed or lost. A regulator holds no gas of its own, so there is nothing inherently problematic about it on an aircraft, though the airline and security screeners always have the final say. Pack it dry with the dust cap in place, in a padded regulator bag or wrapped in soft gear.

Many modern regulators are supplied as suitable for nitrox mixes up to 40 percent oxygen, which is the widely used recreational industry standard, while anything above that requires dedicated oxygen-clean equipment and procedures. Confirm what your specific regulator's manual states, and follow your nitrox training and your fill station's requirements. Never assume a regulator is oxygen-service clean simply because it looks clean or is new.

A yoke (A-clamp) fitting clamps over the tank valve and is the most common connection across much of the recreational world, while a DIN fitting screws into the valve and is standard in much of Europe and in technical diving. DIN captures the o-ring inside the threads, which many divers consider more secure, but yoke is often what rental cylinders provide. Adapters exist in both directions, so check what is used where you dive before deciding.

The octopus is your backup second stage, carried so you can share air with a buddy who is out of gas, or breathe from it yourself if your primary fails or free-flows. It is normally on a longer, brightly colored hose so it is easy to find and hand over under stress. Secure it in the triangle between your chin and the bottom of your rib cage so it is instantly accessible and not dragging through sand or coral.

Store it fully dry, out of sunlight, with the dust cap in place and the hoses in wide loops rather than tightly coiled. Avoid hanging it by the second stages for long periods, which stresses the hose fittings; laying it flat in a padded bag or hanging it by the first stage is kinder. If it has sat unused for a long stretch, have it checked before your next trip rather than assuming it is ready to dive.

This set is supplied with the Apeks DS4 first stage, a compact, cylindrical, over-balanced diaphragm design with a chrome over marine brass exterior. It is environmentally sealed with a standard dry kit that keeps water out of the main spring chamber, and it carries 1 HP port in 7/16" UNF plus 4 MP ports in 3/8" UNF angled for hose routing. Apeks calls the DS4 a time-proven workhorse embraced by the technical community.

The Diver Changeable Exhaust, or DCE, lets you swap between a small exhaust tee and a large exhaust tee. The large tee pushes bubbles wider of your field of view, which underwater photographers often prefer, while the small tee keeps the regulator compact and comfortable. The regulator comes with one set of exhaust tees.

Yes, this set is listed for coldwater use. The DS4 first stage is environmentally sealed with a standard environmental dry kit that keeps water out of the main spring chamber to help prevent ice buildup and to keep silt and contamination out. The second stage adds a patented heat exchanger around the valve mechanism that dissipates the cold of gas expansion while drawing in ambient water warmth.