Auch verfügbar auf 
Deutsch
A dive watch measuring 47.5 millimeters across and rated to 1,000 meters is supposed to feel like a tool. Heavy, deliberate, a little unreasonable. The Ralf Tech WRX Electric Supernova Millenium x CNES is all of those things on paper – and then it weighs 96 grams.
That number is the reason this watch is worth writing about. Everything else on the spec sheet follows from the same decision: build the case so that the material sits only where the pressure goes, and nowhere else.
What 96 grams actually means on a 47.5 mm diver
Weight on a spec sheet is usually the least interesting number. Here it is the whole point.
Put the Supernova on and the size is still there. It does not disappear under a cuff, and it is not trying to. But it does not pull downward, and it does not swing when you move your arm – the two things that make a large diver tiring after an hour. For a watch of these dimensions with this pressure rating, it is far more comfortable than the measurements suggest.
The titanium also changes how it reads. It feels technical rather than precious. If you associate weight with quality, the first few seconds will confuse you: the Supernova handles like equipment, not like jewelry. That is the intention.
How Ralf Tech got the weight out of the case
The material is Grade 1 titanium in aerospace quality T35. That alone does not explain 96 grams – titanium is lighter than steel, but not by half.
The work is in the machining. The case is sculpted and hollowed out from the inside, and deliberately not evenly: up to ten millimeters of material remains where the structure carries load, and everything else is removed. The savings happen where the construction allows it, not where it would be convenient. That is why the watch is still tested and certified to 1,000 meters despite the weight.
The surface is left raw. No polishing, no coating – the titanium is shown as it comes off the machine. It suits the character, and it also means the case will pick up marks faster than a polished steel one. Worth knowing before you buy rather than after.
Why a space agency is involved at all
CNES is the French national space agency, comparable in role to NASA or ESA’s national members, and unusually visible in European missions. A collaboration between an independent French watchmaker and that institution is unusual enough to ask what it actually amounts to.
In this case it is not decoration. There is no printed rocket and no star pattern used as a motif. The material, the movement and the legibility all trace back to requirements that come from the operational environment. The stated range runs from minus 120 to plus 65 degrees Celsius, with heavy vibration and loads up to 8 G. Nobody reaches those limits on a wrist. They do tell you what the construction was aimed at.
The groundwork was laid earlier in the partnership: the case and movement architecture were tested on zero-gravity flights in March 2024. The Supernova is the third watch to come out of that programme, limited to 100 pieces.
5.9 millimeters of sapphire
Above the dial sits a domed, anti-reflective sapphire crystal 5.9 millimeters thick. According to Ralf Tech, that is the thickest sapphire crystal fitted to a series-production watch.
You notice it from the side before you notice anything else. The crystal is not a cover laid on top of the case – it is a visible part of the design, and a large part of why the watch reads as heavily built even though it isn’t heavy.
The dial and the window it came from
The black dial carries a honeycomb structure. The reference is the cockpit instrumentation of the International Space Station – specifically the panels arranged around the large observation window of the Cupola module.
In person it works better than photographs suggest. The structure is three-dimensional rather than printed, and it shifts with the angle of the light. Graphic elements in green and green SuperLuminova C5 provide the accents; the hands are black-coated stainless steel.
Twelve years without opening the case
The movement is an Electric Micro Hybrid, developed in Switzerland for Ralf Tech. Its battery is rated for up to 100,000 operating hours, which the manufacturer translates into roughly twelve years before a service is due.
For a watch built to be sealed against 100 bar, that matters more than it would elsewhere. Every battery change on a 1,000-meter diver means opening a case that was engineered not to be opened. Stretching that interval to a decade or more is a structural argument, not a convenience feature.
Underwater the Supernova is a fully specified diver: a unidirectional bezel with 120 clicks to ISO 6425, a matte black Ceramfine insert with a luminous marker, and a screwed, protected crown.
Where the Supernova stops making sense
The low weight solves one problem and leaves another one untouched. 47.5 millimeters is still 47.5 millimeters. On a narrow wrist the case will overhang, and no amount of titanium changes that.
The raw surface is the second thing to be honest about. It will age visibly. Some people want exactly that; others will be annoyed within a month.
And the price is 4,800 euros. There is no way to talk around that figure.
What I think
What impressed me is how wearable a 47.5 millimeter watch rated to 1,000 meters can be once the weight is engineered out of it. That is a genuinely unusual combination, and it is the reason I would look at this watch twice.
The design remains its own thing. Ralf Tech does not build watches that look like other watches, and the Supernova is a good example. You can like it or not, but you will not confuse it with something else.
At 4,800 euros it is a lot of money – and technically it is defensible: a purpose-developed movement, an elaborately machined titanium case, 100 pieces. The buyer I would point it at is someone who wants a large tool watch but has given up on the weight that usually comes with one. That combination is rare.
Where to get the Supernova
The Ralf Tech WRX Electric Supernova Millenium x CNES is available in my shop: Supernova at the WATCHDAVID Shop.
The key figures at a glance:
- Grade 1 titanium (T35), 47.5 mm diameter, 96 g
- Electric Micro Hybrid RTE001 Long Range, up to 100,000 operating hours
- Sapphire crystal 5.9 mm, domed and anti-reflective
- Unidirectional bezel, 120 clicks to ISO 6425
- Water resistant to 1,000 meters, tested and certified
- Limited to 100 pieces, reference WRX 4104, 4,800 euros
The full specification is listed on the product page. More on the brand in the RALF TECH archive, and the watches themselves in the Ralf Tech collection.
