VIRTUALLY EVERY DIVER TRAINING AGENCY has a set standard for kit configuration. The term “regulators on the right, what’s left on the left” was burnt into my psyche when I first learnt to dive, and still forms the basis for me and many others when setting up our recreational scuba units.
It follows then that regulator manufacturers mostly produce first stages for recreational diving in the same way, with evenly distributed high- and low-pressure ports on either side of the first stage and second stages, designed to be used solely from the wearer's right-hand side.
Historically, one particular regulator maker bucked the trend and produced ambidextrous second stages. These were primarily lateral-exhaust models that could be configured from either side, and they quickly became the regulator of choice for technical divers.
The divers were able to set up their back-mounted twin rigs in virtually any orientation without having to visit a service centre to change the “hand” of their standard second-stage demand valves.
The units were also perfect for side-mounted bail-out and stage decompression rigs.
The manufacturer also produced an ambidextrous second stage with a central hose connection for the same purposes. Unfortunately, this clever design concept seemed to fall out of favour as higher-performing standard-configuration regulators started to appear in dive-shops.
We haven’t seen a take on this type of regulator for many years, but now forward-thinking Italian manufacturer Mares has released an up-to-date version of the ambidextrous second stage. I took a Loop 15X to the Indian Ocean to well and truly test it.

First Stage
The 15X first stage is made from marine-grade brass with a satin chrome finish. The balanced diaphragm design features Dynamic Flow Control (DFC), engineered to minimise the intermediate pressure drop during inhalation and to maximise gas delivery in extreme conditions.
The first-stage valve benefits from the maker’s advanced-coating technology, which is claimed to increase its durability by 600%. Four low-pressure and two high-pressure ports are pre-orientated and evenly distributed on either side of the body. The 15X is available with either international (yoke) or DIN connections, weighing in at 772g and 598g respectively.

Second Stage
The Loop second stage is built almost entirely from abrasion-resistant Ultralight Technopolymer with a vertical design and central hose connection at its base. The hose-to-demand-valve connection is fitted with a lateral swivel and hose-guard.
An internal air bypass tube delivers gas to the mouthpiece in a vortex with a low-pressure area in the centre to help keep the diaphragm down during the inhalation cycle, with the intention of providing sensitive and easy breathing at all depths. Mares call this its Vortex Assisted Design (VAD).
The second stage also features an oversized silicon purge button and twin exhaust valves.
It can be configured from either the left or right side, with the 110cm hose routed under the diver's shoulder. The Technopolymer second stage weighs in at 199g.

Under Water
Before diving with the Loop and 15X combination I spent some time contemplating whether to add a neck bungee to the primary second stage. My worry was that when the regulator was out of my mouth it wouldn’t hang over the shoulder in the same way as a standard set-up, and would therefore be awkward to recover in the traditional manner with a reverse sweep of the right arm.
I needn’t have bothered, because this never became a problem. The long hose, although routed under the arm, proved just as simple to recover.
The big difference from a side-fed regulator was how unrestricted the whole set-up felt. I could swivel my head from side to side or up and down with a freedom that I’d never experienced before, because the lightweight Loop almost felt unattached.
Another advantage was the fact that it never got caught in my camera’s strobe-arm system. With a traditional side-entry second stage I’m forever having to free the intermediate-pressure hose when it gets caught between the arm’s joint and ball-clamp locking handle – deep joy.
There is only one way to describe the breathe – “simply outstanding”. The reg delivered gas in the same smooth, natural way at whichever depth I was. The soft silicon mouthpiece felt comfortable in my mouth, and with the exhaust ports resting snugly on my chin I didn’t have to bite down to keep the Loop in place.
This was turning out to be an amazing regulator, but there was one problem – the exhaust bubbles interfered with my vision, because they passed the front of my mask when I was stationary. I could live with that, given the overall performance of this little Italian opera d’arte.
The hose-routeing was as streamlined as it gets, without any loops of intermediate hose from primary and alternative second stages appearing from behind my right ear.
Instead they were neatly tucked under my arm, following the contours of my scuba unit and well out of harm’s way.
The big purge button was easy to locate, and delivered a progressive increase in airflow as it was depressed to its limit. Upside-down, it didn’t let any unwanted seawater enter the case, nor did it freeflow when spat out.

Conclusion
I had almost forgotten about the virtues of ambidextrous regulator sets, because it’s been a long time since the innovative Poseidon Triton appeared on the market, its horizontal swivel at the base of the second stage marking a breakaway in traditional regulator design and giving it an almost cult status.
Mares’ new concept of a vertical hose routed vertically to the bottom centre of the second stage is, as far as I know, unique, marking the Loop as the first of its kind. It’s a simple concept and one that has been well-built by the team at Mares.
My regular dive buddy Bruce (the Italian Stallion) Milani-Gallieni insisted on trying the regulator out during the test dives in the Maldives. His initial response was “incredibili, Mares bravo!” and it was testament to this brilliant piece of dive-kit that I had a fight on my hands to get it back from him.

SPECS
PRICES: Loop 15X £263. Loop Octo £105
FIRST STAGE: Balanced diaphragm
PORTS: 4 lp, 2 hp
SECOND STAGE: Vertical connection
USER ADJUSTABLE: No
WEIGHT: A-clamp 1.146kg, DIN 972g (including hose)
OPTIONAL EXTRAS: CWD Dry Kit
CONTACT: mares.com
DIVER GUIDE 10/10