Product Description

Apeks ATX40 DS4 Stage 3 Set

Before the XTX range of regulators came along, the ATX models ruled the seas. The ATX40 is still available today and offers a fully balanced first and second stage with cold water capability (can be used in all temperatures including those below 10 C / 50 F).


This high-performance regulator boasts an over-balanced first stage coupled with a pneumatically balanced second stage.

The smooth, quiet breath is sure to enhance your diving enjoyment.

Suitable for coldwater use thanks to its first stage environmental dry seal and second stage heat exchanger.

Compatible with EAN40 out of the box.


First Stage:

– Uses the DS4 first stage
– Unique over-balanced, diaphragm design – as the diver descends, the over-balancing feature allows the medium pressure gas in the hose to increase at a rate faster than ambient. This results in superior performance at depth.
– 1 HP port and 4 MP ports are available.
– An environmental dry system keeps water out of the main spring chamber thus preventing ice buildup and keeping silt and contamination out.
– Available in DIN and yoke.

Second Stage:

– Pneumatically-balanced second stage results in smooth, easy breathing.
– The large purge button on the ATX is easy to operate even with thick gloves.
– The integrated venturi control provides a performance boost at depth while preventing unwanted freeflow at the surface.
– An extremely efficient exhaust valve improves the breathing performance of the regulator.
– The Comfo-bite™ mouthpiece virtually eliminates jaw-fatigue.
– A heat exchanger (patented) which surrounds the valve mechanism, dissipates the cold caused by gas expansion while drawing in the warmth of the ambient water.
– Offers a compact, integrated exhaust tee.

ATX40 Octopus

– The XTX purge buttons are large and easy to operate. A 2-stage progressive purge is used. Press the purge on the side for a lower flow rate, useful where more control is required such as filling lift bags etc, then press in the centre for the full effect of the purge, i.e. when regulator clearing etc.
– Can be converted from a right-handed hose configuration to a left handed one. The process of changing the regulator to a left-handed configuration is both quick and simple. However, this procedure must ONLY be performed by an APEKS Authorised Service Technician.
– Braided flexi-hoses are now standard on all models. These hoses are lighter weight, more flexible and more durable.
– Compatible with EAN40 out of the box.
– Pneumatically-balanced second stage results in smooth, easy breathing.
– The large venturi lever has a soft touch rubber grip, which makes it easier to locate and use. The lever reduces the amount of grit ingress and therefore resists any possible friction giving a smooth operation.
– The Octopus is manufactured with active protection against infection as all moulded parts are produced with an additive that kills MRSA, protects against E-Coli, bacteria and fungi, and is also very effective against viruses, mould, yeast and algae.
– A silicone exhaust valve improves the breathing performance of the regulator.
– The Comfo-bite™ mouthpiece virtually eliminates jaw-fatigue
– Suitable for cold water use (below 10 C / 50 F).