From the WatchTime archives: If you want to climb mountains, explore caverns, or undergo underwater ordeals, these watches will blithely master such extreme situations. But their attributes can also be useful in everyday life.
Light Fantastic: Ball Watch Engineer Hydrocarbon Black
A watch designed for extreme missions must be easy to read in every situation. When nighttime legibility is at stake, everything depends on how long the dial’s luminous material continues to glow. Some watches can be read after eight hours in darkness, but even Super-LumiNova gives up the ghost if the gloom lasts much longer. This is not the case when the dial’s illumination relies on tritium gas. Here, little glass tubes are coated with a luminous substance on their inner surfaces and filled with safely captured tritium, which activates the luminescent material that lines the tubes. The tubes continue to gleam brightly, even after spending years in total darkness. Watches equipped with these luminous tubes are frequently used by the military and by members of the Special Forces. Ball Watch uses this technique in its Engineer Hydrocarbon Black, which has a titanium case coated with black DLC, a scratch-resistant ceramic bezel and a 5.3-mm-thick sapphire crystal. A patented system protects the crown against impacts. Ball Watch uses another patented system to modify the shock absorbers for the balance so the watch is more resistant to vibrations. Ball’s self-winding caliber, which is based on Sellita’s SW 200, is COSC-certified. This 42-mm watch is water resistant to 300 meters. Price: $4,699.
Brawn in the Brine: IWC Aquatimer Automatic 2000
Saltwater can cause pitting in the surface of a watch’s steel case. The case can become speckled with tiny holes, behind which lurk larger cavities. Steel’s ability to resist corrosion by saltwater is measured by its PRE value: PRE means “pitting resistance equivalent.” A PRE value of 32 is considered to be resistant to corrosion by seawater. Higher PRE values provide greater resistance. Most steel cases are made from 316L steel, which has a PRE value of only 24. These cases should always be rinsed in fresh water after exposure to seawater. Rolex’s cases are made from 904L steel, which has a PRE value of 35, and is quite resistant to corrosion by saltwater. The submarine steel that Sinn uses for its divers’ watches has a PRE value of 38. But titanium is an even better choice for watch cases because this metal is totally impervious to corrosion by saltwater. The IWC Aquatimer Automatic 2000 has a titanium case. It is water resistant to 2,000 meters and is equipped with self-winding in-house Caliber 80110. Price: $9,500.
Taking the Field: Omega Seamaster Ploprof 1200M
Magnetic fields can damage watches. Parts of the movement can become lastingly magnetized, which severely interferes with the accuracy of the rate. The invisible force of magnetism lurks in our everyday surroundings: for example, stereo loudspeakers or smartphones generate magnetic fields. The best protection from magnetism is offered by Omega’s Master Chronometer in-house movements, which have been certified by METAS (Switzerland’s Federal Institute for Metrology). Antimagnetic materials inside these watches ensure that they can cope with magnetic fields up to 15,000 gauss. This protection is 15 times greater than that provided by a conventional soft-iron inner case. The Omega Seamaster Ploprof 1200M is powered by Omega Master Chronometer Caliber 8912. It has a 48-mm titanium case. The watch’s ceramic diving bezel is released and locked by a distinctive pusher at 2 o’clock. The crown is protected by a bracket that cannot be opened until the crown is unscrewed. The Ploprof is water-resistant to 1,200 meters. Price: $13,800.
Up to Scratch: Panerai Luminor 1950 3 Days GMT Automatic Ceramica
Scratch-resistant cases aren’t only useful for extreme athletes, but also for mere mortals in everyday life. The sapphire crystal that’s used to protect most watch dials has a hardness of 2,000 Vickers and is, therefore, very scratch-resistant. Steel cases, on the other hand, are more vulnerable: the hardness of 316L stainless steel, the most commonly used steel alloy, is around 220 Vickers. The case of the Panerai Luminor 1950 3 Days GMT Automatic Ceramica is made of zirconium-oxide ceramic that has a Vickers hardness of 1,200, which is significantly harder than steel, but is also more susceptible to breakage. The 44-mm case houses self-winding in-house Caliber P.9001. The sandwich-style dial with beige Super-LumiNova guarantees good legibility in the dark. Price: $11,200.
Pressure Suitable: Rolex Deepsea
A watch’s resistance to pressure really cannot be too high. While professional divers descend to a maximum depth of only 300 meters, additional pressure is generated by a diver’s motion. Furthermore, high resistance to pressure makes a watch more robust. Rolex’s Deepsea is a divers’ watch that uses innovative technology to combine pressure resistance and a compact case. The case is 44 mm in diameter and 18 mm high, yet the watch resists pressure to a depth of 3,900 meters. The case is made of three different materials: a 5.5-mm-thick synthetic sapphire crystal; a 3.28-mm-thick back made of grade-five titanium; and an intermediate inner ring made of Biodur 108 steel, to which the crystal and the back are affixed. When subjected to pressure, these materials undergo less distortion than the steel alloys typically used for watch cases, so Rolex can build a slimmer watch. The Deepsea’s movement, Rolex automatic Caliber 3135, also has the reputation of being extremely robust. Price: $12,350.
Beating the Heat: Sinn EZM 7 S
Extreme temperatures can wreak havoc on a watch and cause it to stop running altogether. That’s why Sinn uses special oil and follows narrow tolerances to build the EZM 7 S, which is specifically designed for use by firefighters. Thanks to these features, this watch is guaranteed to remain operational at temperatures ranging from -45° C (-49 degrees F) to +80° C (+176 degrees F). Every timepiece is individually tested at these extreme temperatures. The calibrated rings on the EZM 7 S’s dial are printed according to firefighters’ specifications and are helpful when the wearer is using a protective breathing apparatus. The 43-mm stainless-steel case is fully “tegimented” using Sinn’s special surface treatment process for hardening to create a protective layer against scratches. Sinn’s stay-dry technology inside the case guarantees that the sapphire crystal never fogs up. An inner case made of soft iron protects Caliber ETA 2893 from magnetic fields up to 1,000 gauss (80,000 A/m). Price: $2,890.