Apeks MTX-R Stage 3 Set




The MTX-R is based on the MTX military regulator and is a super tough, rugged, high performance, go anywhere regulator. The MTX-R has excellent cold water performance and has a greatly reduced risk of free flow. This has been achieved by improving several areas, including an innovative endcap solution that solves a long-challenged reality for cold-water divers of first stage freeze up. This regulator is designed to meet all aspects of the NEDU (Navy Experimental Dive Unit) military requirements for diving in very cold water. The MTX-R is highly reliable and also very easy to service out in the field.




First and Second 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 faster rate than ambient. This results in superior performance at depth
  • Compact environmentally dry sealed diaphragm system completely eliminating the maintenance issues associated with silicone, oil or grease filling
  • Break through, innovative over-moulded first-stage endcap & environmental diaphragm helps prevent ice build-up that can cause first stage free flow in extreme circumstances. Also protects the first stage from impact damage
  • Easy to grip DIN hand-wheel or over-moulded yoke hand-wheel, only requires one hand to release
  • DIN, Yoke and M26 Thread available, 300bar, 232bar and M26 300bar (O2) respectively
  • 5 x 3/8” UNF (Unified National Fine) medium pressure ports
  • 2 x 7/16” UNF high pressure ports
  • The 5th 3/8” UNFmedium pressure port includes a protective bumper when not in use
  • Forged first stage body with heat exchanging ribs for maximum thermal performance
  • Angled HP ports for optimal hose routing and fitting of transmitters
  • Forged rotating turret with medium pressure ports in a parallel direction for improved hose orientation
  • Ribbed diaphragm clamp for improved heat exchange in cold water conditions
  • Double swivel hose for greater freedom of movement and comfort
  • Tested for Octopus use – EN250A to 60 meters cold water
  • Nitrox/Oxygen compatible – Up to 40% O2 outside the EU (European Union), within the EU anything above 21% O2 must use an M26 Connection
  • Simple to use with no dive adjustment controls and reduced chance of free flow occurrence, pre-settable cracking effort or venturi control by an Apeksapproved qualified technician
  • High performance pneumatically balanced lever operated poppet valve
  • Large, diver friendly self-flushing controllable purge button
  • Front cover with over-moulded elastomer incorporates a formed chrome plated brass plate improving durability of the second stage
  • Large protective elastomer bumpers on the side and on the top to protect the second stage from impacts and scratches in the most vulnerable places
  • Reversible second stage for either a left or right hand gas supply configuration
  • 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
  • Removable bungee necklace with lock out feature for retaining second stage in the mouth of an unconscious diver during rescue and to assist with jaw fatigue
  • Comfo-bite mouthpiece
  • Flexible nylon braided hose has better cold water performance than traditional rubber hose
  • Simple service kits
  • Easy to service
  • Colour coded octopus hose



Weight DIN – 1.193 kg (2.63lbs)
Yoke – 1.339 kg (2.95 lbs)
Max working pressures 1st Stage: DIN – 300 bar (4351 psi) Yoke – 232 bar (3365 psi) 2nd Stage: 9-10 bar (131-145 psi)
Part No.s AP0060 – MTX-R 1st and 2nd stage with yoke
AP0061 – MTX-R 1st and 2nd stage with DIN
AP0063 – MTX-R 1st stage DIN connection
AP0062 – MTX-R 1st stage yoke connection
AP0064 – MTX-R 2nd stage
Certified to EN250A
Maintenance kit no.s 1st stage – AP0241
2nd stage – AP0219
Temp range 32.9°F – 12.778°F
0.5°C – 55°C
Connection Types DIN and Yoke
Service intervals Annual
Key features Cold water use
Easy to use
Durable & reliable
Intended use Recreational, technical and extreme cold water diving
WOB 1.75 J/l
Nitrox/Oxygen compatible Up to 40% O2 outside the EU (European Union), within the EU anything above 21% O2 must use an M26 Connection


MTX-R Octopus

This octopus uses the same second stage as the MTX-R.

  • Includes left / right reversibility, coldwater capability and the performance you would expect from an Apeks pneumatically balanced valve
  • The unit has a high visibility yellow front cover, yellow accent pieces and a 36” braided flex yellow hose
  • Comes standard with small exhaust tee