Appeared in DIVER October 2008

John John Bantin has been a full-time professional diving writer and underwater photographer since 1990. He makes around 300 dives each year testing diving equipment.


EVEN I AM NOW CONFUSED by the proliferation of Mares first stages that resemble cut-down versions of that old, well-trusted yet massive lump of brass, the MR22.
The latest, pared-down MR22 is lighter than before, while the MR42 looks similar but is actually smaller overall. The MR32 appears to be somewhere in the middle, but with a plastic coating. Are you still with me
The MR32 is said to feature NTT, another of those Mares acronyms that, in this case, stands for Nano Thermoconductive Technology.
Any the wiser
My computer dictionary tells me that nano technology is the branch of technology that deals with dimensions and tolerances of less than 100 nanometers, especially the manipulation of individual atoms and molecules.
Thermoconductive is obviously to do with conduction of heat, so the term doesnt seem to amount to much.
Some things are designed more for buying and selling than for using, though the price of this regulator certainly makes buying less painful than it might be.

First Stage
This diaphragm-type first stage is claimed to be less likely to be affected adversely by cold, fresh water - but then, Mares regulators never seemed to have any problem in this department, thanks to the huge amount of metal normally employed in both first and
second stages.
As usual, this one has four medium-pressure ports at convenient angles and two hp ports angled well away from the others to ensure that hose routes are always convenient. Apart from the coating, its recognisable from the red letter T emblazoned on it.

Second Stage
Here I get even more confused. The second stage is made from a technopolymer case material that allows for heat transfer, just like metal. Why bother, when Mares already makes excellent metal second stages that do this
These second stages are also notable because their Bi-pass Tube design obviates the chances of exponential free-flow due to a pressure drop behind the front diaphragm caused by air flowing cleanly by at high speed.
Other manufacturers have to include a little flap or vane that can be introduced into the flow to disrupt the venturi effect pre-dive.
I even recently heard a dive-instructor suggest to a newly qualified diver that if he left his regulator in the Predive position, he would use less air. I was not rude enough to question his obviously faulty reasoning!
Mares seems to be bowing to be departing from its own unique and successful solution to this problem, because it has included an additional Predive/ Dive control on this new second stage.
It works slightly differently from that of other manufacturers. Instead of a vane, the Predive/ Dive switch simply restricts how far the front diaphragm can depress and open the second-stage valve.
Perhaps it was pressure from US dealers claiming that they couldnt sell a regulator without knobs or switches, but Mares has solved a problem that was probably only there in the minds of dealers who sold competing products.
Of course, this unit still has the admirable Bi-pass Tube too, which really makes the switch redundant. Without the air forming a venturi vortex effect, thanks to that tube, a normal venturi plus/minus vane wouldnt have any effect, either.

Purge Control
Theres no problem finding this particular purge control. Its big, bold and easily applied, even with thick gloves. As usual with Mares regulators, its progressive without introducing any risk of your tonsils being blasted down your throat.

Mares regulators have always been my first choice when it comes to diving in fresh water at less than 4C, but despite the marketing intentions of the manufacturer, I have to say that I tried out the Prestige 32 NTT in the Red Sea in July!
Surrounded by British divers with their 15-litre tanks and 3-litre ponies doing dives at
what some would call snorkelling depths, no-one felt it necessary to comment that I
was inappropriately equipped in the breathing department.
The Prestige 32 NTT did not breathe as easily as some of the more expensive Mares regulators, and I was conscious of every inhalation, but it did the job. Perhaps it was simply a bit noisier than others. I certainly didnt find that I used less air than usual.

Aqua Lung Titan LX Supreme, £250
Oceanic Delta 4 DX4, £255
Cressi-sub Ellipse Titanium, £269

Divernet Divernet
FIRST STAGE Diaphragm-type
PORTS 2hp, 4mp
DIVER GUIDE width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100%