In 1908 Wilsdorf registered the trademark "Rolex" and opened an office in La Chaux-de-Fonds, Switzerland. The company name "Rolex" was registered on 15 November 1915. The book The Best of Time: Rolex Wristwatches: An Unauthorized History by Jeffrey P. Hess and James Dowling says that the name was just made up. One story, never confirmed by Wilsdorf, recounts that the name came from the French phrase horlogerie exquise, meaning "exquisite clockwork" or as a contraction of "horological excellence". Wilsdorf was said to want his watch brand's name to be easily pronounceable in any language. He also thought that the name "Rolex" was onomatopoeic, sounding like a watch being wound. It is easily pronounceable in many languages and, as all its upper-case letters have the same size, can be written symmetrically. It was also short enough to fit on the face of a watch. Rolex is the largest manufacturer of Swiss made certified chronometers. In 2005, more than half the annual production of COSC certified watches were Rolexes. To date, Rolex still holds the record for the most certified chronometer movements in the category of wristwatches. Rolex SA is owned by the private Hans Wilsdorf Foundation, which is registered as a charity and does not pay corporate income taxes. In 2011, a spokesman for Rolex declined to provide evidence regarding the amount of charitable donations made by the Wilsdorf Foundation. In Geneva, where it is based, it has gifted, among many things, two housing buildings to social institutions of Geneva. Rolex was also the second watch company to create a water resistant wristwatch that could withstand pressure to a depth of 330 feet (100 m). Wilsdorf even had a specially made Rolex watch (the watch was called the "DeepSea") attached to the side of Trieste, which went to the bottom of the Mariana Trench. The watch survived and tested as having kept perfect time during its descent and ascent. This was confirmed by a telegram sent to Rolex the following day saying "Am happy to confirm that even at 11,000 metres your watch is as precise as on the surface. Best regards, Jacques Piccard".
Although the first Rolex GMT Master model was available only in stainless steel, as it was created as a functional work watch, Rolex has been making luxury models in both mixed steel and gold, and all-gold since the 1950s, and there are even {special|exotic variations that have creative styling that use precious stones. As I mentioned earlier, the Explorer II wears a little slimmer but is a touch wider than the GMT II, so which one you prefer comes down to personal preference and the kind of clothes you wear. If you tend to wear tighter fitting shirts and jackets, then you might find the GMT Master II more likely to get stuck on your cuffs. The most obvious difference between the watches is in the bezel. The Explorer II has a fixed bezel in brushed stainless steel and engraved 24-hour numerals painted black. The GMT Master II comes with a Cerachrom bezel and this, if you like the look of it, has some clear advantages. Ceracrom is a ceramic compound made and developed exclusively by Rolex. It’s almost entirely scratch-resistant and is unaffected by UV rays. It’s being used more and more by Rolex and features in the latest Submariner and the recently released Cosmograph Daytona. The numerals are etched into the bezel and then coated with a layer of platinum for maximum legibility and durability.
The Rolex GMT-Master wristwatch was originally designed in collaboration with Pan American Airways and issued by the airline to their crews on long-haul flights. ("GMT" in the name stands for Greenwich Mean Time also known as Coordinated Universal Time). The original GMT Master watch has a 24-hour display fourth hand complication directly linked to and displaying the same time zone as the standard 12-hour hand. This GMT hand enabled the crews to set the watch to GMT or another time zone, and, using the rotatable 24-hour scale bezel, set to the correct offset, a second time zone could be read. GMT or UTC is the time zone that is required for all aviation planning, weather forecasts, schedules and other paperwork. An updated Rolex GMT Master II was released in 2005. This new model features a number of technical changes, such as Rolex's patented Parachrom hairspring as well as a larger Triplock crown (from the diver's watches). The new model also has several cosmetic changes, such as larger case, hands and hour markers and also a new bezel made using an extremely hard ceramic material that is designed to be more scratch and fade resistant. Also included in the update is a new and more luxurious style of bracelet that has heavier solid links and a machined clasp. The stainless steel version now joins the precious metal versions by having highly polished centre links on its bracelet, which gives the watch a more dressy appearance but can be prone to scratches when used as an everyday watch.