Italian gear giant Mares took advantage of this high-quality, lower-cost technology when it first introduced its EOS range of underwater torches. The originals have recently been upgraded, with lamps that use a dedicated rechargeable power source and have adjustable light beams.
The new range is prefixed RZ, which stands for Rechargeable Zoom.

The Design
There are four lamps in the new EOS RZ range, and all have the same features but differ in size, output and burntimes. The bodies are crafted from marine-grade anodised aluminium alloy, finished in a dark metallic silver colour.
The switches are external and magnetic, which means they’re sealed from the internal components, helping to protect the lamps from flooding. Each switch has four functions, on/high, low, flash and off.
Illumination comes from Cree LED chips, which vary in type and number depending on the lamp model. Single, dedicated rechargeable li-ion batteries supply power and are charged with the battery in the lamp body via an in-house USB connection, which is accessed by removing a double O-ring protected screw cap.

A small LED light that shows red for charging and green when the charging process is complete indicates the charge status.
Although outputs and burntimes vary for each model, they all deliver light at a colour temperature of 5700K with adjustable beam angles that range from 12° to 75°.
They are depth-rated to 120m, and come with a wrist lanyard.

In Use
I took the smallest EOS 2RZ model as a back-up and the largest EOS 12RZ as my primary light on a Caribbean trip to see how they performed.
The smaller of the two delivers a claimed output of 220 lumens on full power and 60 on low from a single Cree XPE LED chip that is said to burn for 180 minutes on its lowest setting.
The EOS 12RZ has three Cree XP-G2 LED chips that collectively deliver 1200 lumens on full power and 300 on low, with stated burntimes of 120 minutes on full power and 300 on low.
The switching process was simple – a single forward push of the sliding magnetic switch turned the lamp on at full power; if I pushed it again within 10 seconds it switched to low, and then again within 10 seconds to a flashing mode. This, I’m assured, is the SOS mode, and not designed to make everything seem as if it’s moving in slow motion.
If the switch is left untouched for longer than 10 seconds the next push switches the lamp off, and it required me to scroll through the settings again to get to the desired mode.
By rotating the lamp-head, the light beam could be tightened or widened. This is achieved by the LED head and reflector moving away or towards a small lens fitted to the glass face.
The widest setting delivered an even, soft pool of light and the tightest a narrow, penetrating beam. On both lamps, anywhere between these settings a darker spot of light was clearly visible in the centre of the beam, with a brighter halo surrounding it.
Under water during the day the 12RZ worked well with the beam set at its narrowest.
I was able to look under shadowed overhangs and into dark crevices to spot small creatures hiding away, and the bright 1200 lumens overcame the ambient light, revealing the true colours of coral, sponges and fish.
After dark on a few night-dives the torch came into its own. On low power and the widest beam it lit my way without destroying my night vision, and at this setting was ideal for illuminating my instruments. It didn’t send the local wildlife scurrying away with their fins over their eyes.
With the beam set at its narrowest and the lamp on full power, the 12RZ was at its best. The tight beam didn’t light suspended particles at its periphery and cut through the water, ending in an even spot of light on my chosen target.
I did try the flashing mode, but quickly became aware that it was inducing vertigo, as my mind tried to make sense of what looked like a nightclub scene.
I switched modes and got on with my dive.
The lamps were very tactile in use. The knurled finish on the main body had a nice feel and was easy to grip, and the rubber around the lamp-head provided a slip-resistant surface when zooming.

After the trip I put all four lamps through my hi-tec, real-world, burntime measurement system. OK, I threw them in my yellow plastic bucket of water, with a stopwatch to time their durations.
Rather than bore you with the multiple results I can summarise by telling you that they all fell short of the maker’s claimed durations, but not by much.
The biggest difference was with the 4RZ. Its claimed times are high 150 and low 480min, and it actually died after 135 and 445min.
The nearest was the 12RZ, which gave up the ghost within five minutes of both its stated times. This isn’t an exact science, because li-ion batteries seem to have a mind of their own with regard to discharge rates and vary, sometimes considerably, from test to test and day by day.

Mares EOS RZ lights are made to a high standard and have some nifty features. The zoom function is useful and has practical advantages. I found that to get the best-quality beam it was necessary to use it at its widest or narrowest setting – anywhere between substantially degraded its quality.
The USB charging system is a great addition to any torch because you don’t have to own a dedicated charger – a smartphone plug or computer is all that’s needed.
The only real disappointment with all these lamps was the lack of a proper lock to stop them being accidentally activated.
The rear end-cap needed to be removed to disconnect the batteries, leaving the main twin O-rings exposed.
There’s no doubt that these all-metal underwater lamps will prove a popular addition to divers’ kit-bags, because they’re good-quality products that deliver decent performance and represent great value for money.

PRICES 2RZ £89, 4RZ £113, 7RZ £137, 12RZ £178.
MAXIMUM OUTPUT (lumens) 2RZ 220, 4RZ 400, 7RZ 700, 12RZ 1200.
SETTINGS High, low, flash, off
BATTERIES Single rechargeable li-ion
CHARGING In-house, USB connection
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