Introducing The Ressence Type 7 GMT, The First Dual Time Zone Ressence
The first Ressence GMT has the first integrated bracelet from the company as well.
The Type 7 GMT makes use of two signature Ressence features – these are the ROCS, or Ressence Orbital Convex System, and the oil-filled upper case. Both features were found in the very first Ressence watch, the Type 1, which was shown as a prototype at Baselworld in 2010 and Ressence has over the subsequent fifteen years, shown just how versatile the system can be. Today Ressence is launching a new complication – the Type 7 GMT, which is the first Ressence watch capable of displaying the time in two time zones simultaneously.
The Type 7 GMT uses a variant of the ROCS system called the ROCS 7, which designates the GMT display variant. Like all Ressence oil-filled watches, the case of the Type 7 is divided into an upper and lower half, separated by a titanium membrane. The lower half of the case contains the automatic winding system and the going train, as well as the lever escapement, balance spring, and balance. The upper half of the case is filled with oil, which has the same refractive index as the overlying sapphire crystal (the refractive index of a material is the degree to which the path of light passing through the material is bent). The result is that the crystal seems to vanish and the ROCS display appears to be floating right on the surface of the crystal; the effect drew crowds when Ressence showed their first prototypes in 2010 and the display system has lost none of its fascination and visual impact in subsequent years. The oil is formulated so that it won’t cause deterioration of the Super-LumiNova used on the ROCS display.
The reason that the oil has to be confined to the upper half of the case, is that it would be impossible for the balance to oscillate if it were immersed in oil, as the oil’s too viscous – there are some dive watches, designed to operate at depths of thousands of meters, which have oil-filled cases to resist compression, but those use quartz movements. In order to set the ROCS display, some means had to be found to couple the mechanical components in the air-filled lower case, to the ROCS system in the upper case, and eventually Benoît Minitiens, the founder of Ressence, hit upon the idea of using very small, very powerful permanent magnets in the upper and lower case.
The magnets are extremely tiny – one millimeter in diameter and only half a millimeter thick – but they still generate enough attractive force to allow the upper and lower mechanisms to couple without an actual mechanical coupling mechanism. Magnetic field strength falls off rapidly with distance but just to be on the safe side, the ROCS magnets are contained in an alloy cage very much like the mu-metal/soft iron inner cases found in antimagnetic watches. Such materials provide a preferred pathway for magnetic field lines and prevent magnetic contamination of the balance spring. A magnetic field doesn’t need to be strong enough to magnetize or outright stop a watch to cause problems; magnetic fields, even weak ones, can mess up the temperature compensation properties of a balance spring, so Ressence is doing the right thing in taking out some insurance.
The display for the Type 7 follows the same basic layout as the Type 1, but with some modifications. The entire ROCS display rotates on its center axis once per hour and carries the indicator for the minutes. The hours are read off a smaller subdial, which also contains the oil temperature indicator. The oil in the upper case expands and contracts slightly with changes in temperature and the oil temp gauge is there to show that the oil is in the optimum range for correct functioning of the ROCS system (the change in oil volume is compensated for by an internal system of bellows which can expand and contract). The temp gauge changes color as the temperature changes, with green corresponding to the middle temperature range; the window goes red at the high end of the temperature range and blue at the low end. Movement of the indicator is thanks to a coiled bimetallic strip, which lengthens and contracts as the temperature changes and with the bellows system, the watch can operate in a wide range of temperatures – minus 5º to +55º degrees Celsius, which is 23º to 131º Fahrenheit (may you never need the upper end of the scale).
The indication at 12:00 in the picture is the “runner” which rotates once every 120 seconds, and which acts as a function indicator. Finally, the second time zone indication is shown in a 24 hour format in the subdial at 4:00.
As with all ROCS watches, the subdials are all geared so that they remain upright, no matter their position on the dial as it rotates.
The procedure for setting the watch is different from other GMT watches although it will be familiar to anyone who’s spent some time with other Ressence watches. Instead of being controlled from a crown, Ressence ROCS watches are controlled by rotating the caseback clockwise and counterclockwise, and winding and setting for the Type 7 is basically a variation on the procedure for the original Type 1. The first step is to wind some energy into the mainspring, which Ressence refers to as “kickstarting” in which you rotate the caseback. This will wind energy into the mainspring and will also cause the ROCS to rotate. You then set the 24 hour indication by turning the caseback so that the time goes backwards, until you reach the correct time zone in the GMT indicator (which functions as the home time indication). To set local time, turn the caseback so the time goes forward.
The Type 7 is also a bit of a departure for Ressence in terms of design – generally (although not always) the lugs of a Ressence watch are either absent, or treated in such a way as to preserve the biomorphic lines of the case. The Type 7 has a case in titanium with sharper, polished transitions between the clearly defined upper case and case middle, which are continued on the upper edges of the titanium bracelet links. Strictly speaking, I don’t know that I would call this an integrated bracelet design inasmuch as theoretically, you could remove the bracelet and substitute a strap but the bracelet is certainly an integrated one from a design standpoint.
The Type 7, despite the caseback winding and setting system, is water resistant to 50 meters (the Type 1 by comparison is “splash resistant” per Ressence). The more robust water resistance is courtesy the Ressence Compression Lock System, which lets you lock the caseback for water resistance and unlock it for winding and setting; this is the system that Ressence first introduced in its Type 5 diver’s watch, which is water resistant to 100 meters and which, with its one-way bezel, abundant lume, and function indicator, is a fully ISO 6425 compliant dive watch. The Type 5 has a separate locking ring along the edge of the caseback, but in the Type 7 the entire caseback can be screwed down to seal the watch, or unscrewed for winding and setting, just like a conventional screw down crown.
The Ressence Type 7 is being launched in two versions – Night Blue, and XV Aquamarine – with a ceramic bezel for the Night Blue, and an anodized aluminum bezel for the XV Aquamarine. The XV Aquamarine is a limited edition, celebrating the 15th anniversary of Ressence, with 80 pieces available worldwide; it will be available only in 2025.
Despite the absence of a conventional crown or pusher system, the Ressence Type 7 appears to be easy to set and changing local time is easily done via the rotating caseback. The titanium case and bracelet make it a light, comfortable, and practical GMT watch and it is certainly not like any other GMT watch available from any other brand (as a matter of fact, except for other oil filled ROCS watches, it is not like any other watch from any other company, period). The copious use of lume, which is typical of Ressence watches and an intrinsic part of the design of oil filled ROCS watches, will make it a highly legible travel companion as well – one that stands out, and then some, from the generally somewhat dourly functional appearance of many conventional dual time zone watches. If you want to travel with style – really original style – this is a great way to go.
The 1916 Company is proud to be an authorized Ressence retailer.
The Ressence Type 7 GMT: case, grade 5 titanium with two compartments (upper filled with 2.95 ml of oil) 41mm x 14mm, 50M water resistant with sapphire crystal. Dial, convex grade 5 titanium, with three inclined eccentric satellites. Movement, ROCS 7 module with Ressence Compression Locking System (RCLS), automatic, 36 hour power reserve running at 28,800 vph in 37 jewels. Hours, minutes, GMT, runner, and oil temperature gauge. The XV Aquamarine is a limited edition of 80 pieces world wide, and is available only in 2025. US price, $42,500.