reen and yellow cosmetic pieces clearly identify that this regulator is dedicated for high-percentage oxygen use.

The compact DS4 first stage has four medium-pressure ports and one high-pressure port (it does not feature the rotating turret found on the DST first stage).

Features an innovative Diver Changeable Exhaust system (DCE). This system gives the diver the ability to change from a small exhaust tee to a large exhaust tee. This gives the user a choice, wider exhaust tee for minimal bubble interference (essential for underwater photography) and narrow exhaust tee for a smaller compact comfortable regulator. Only the narrow exhaust tee is supplied with the regulator.

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.

Available in yoke or DIN configuration.

A braided flexi-hose comes standard. These hoses are lighter weight, more flexible and more durable.

Suitable for coldwater use (below 10 C / 50 F).

This regulator is suitable for use with up to 100% oxygen.

First Stage:

• 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.
• 2 HP ports and 4 MP ports are angled for optimum hose routing.
• An environmental dry system keeps water out of the main spring chamber thus preventing ice buildup and keeping silt and contamination out.

Second Stage

• Pneumatically-balanced second stage results in smooth, easy breathing.
• 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.
• 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.
• Easy-to-grip opening effort control knob keeps the diver in control.
• The second stage is manufactured with active protection against infection as all molded 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.
• 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.