For a novice in the watchmaking world, it might be difficult to orient oneself through the different models available in a vast catalogue, such as the Rolex’s one. With this buying guide, we aim to explore the current catalogue, explaining the main differences between a precise series of models: the watches characterized by the oyster case and time-only movements, without any specific function of the bezel.
The first common characteristic among the selected watches is the oyster case, which was introduced in 1926 and was the world’s first waterproof case for a wristwatch ever created, thanks to its patented system of screwing down the bezel, the case back and the winding crown against the middle case. Secondly, all the watches show a simple movement with only the time (and potentially the date and day) indication, without any specific function of the bezel. Therefore, among today’s lineup we will focus our attention on three watches from the Classic line (Oyster Perpetual, Datejust, Day-Date) and three watches from the Professional line (Explorer, Millgauss and Air King).
Classic – Oyster Perpetual

Starting from the basics, the first watch we describe is the Oyster Perpetual, the essence of the oyster. This watch benefits from all the most important features of a Rolex: excellent chronometric precision, 100 meters waterproof Oyster case and self-winding movement thanks to a Perpetual rotor. This timepiece is exclusively made out of Oystersteel, Rolex’s proprietary steel alloy, and displays only hours, minutes and seconds. It is available with different sized cases: 28, 31 and 34 mm powered by the 2236 caliber and 36 or 41 mm powered by the 3230. The oyster perpetual features a range of dials that can have different colors representing the purest form of a watch.
Classic – DateJust

Moving a step forward from the complication perspective, in 1945, to celebrate its 40th anniversary, Rolex presented the Datejust with the jubilee bracelet and the knurled bezel as distinctive characteristics. This watch features the time indication and the date in a window at three o’clock (whose name comes from), it is powered by an automatic caliber and it is waterproof down to 100 meters. Believe it or not, the Datejust introduced one of the most common and requested complications in today’s world (date at 3 o’clock), defining true elegance and iconic design that have since become the archetype of the Rolex classic watch.
Today the Datejust can be purchased in many different combinations, with sizes of 28, 31, 36 and 41mm; it can be made of Oystersteel, Oystersteel and yellow, rose or white gold, while the 31mm size can also be configured as a full gold piece. For the 28 and 31mm case the selected movement is the 2236, while for all the others it is the 3235. It can be configured with a knurled gold bezel or a smooth one, in combination with a jubilee or oyster band and many different dial colors. During the 20th century, the Datejust has been seen on the wrist of major figures such as Winston Churchill or Martin Luther King, spanning eras without losing its modern touch.
Classic – Day-Date

The Day-Date was the first watch to display the date and the complete day of the week through two separate windows, added to the waterproof oyster case and the automatic Perpetual rotor. It has always come in precious metal only, being for a long time the most sophisticated watch offered by Rolex and becoming the watch of prestige per excellence in the lineup. Today it can be found in two different sizes, 36mm and 41mm both using the 3255 caliber, crafted in white, yellow, rose gold and platinum with different dial colors (including precious or semi-precious ones) for each metal. Rolex describes this timepiece as the “presidents’ watch” of the past and leaders of the future.
Professional – Explorer

Moving on to the Professional side of the collection, the first watch we introduce is the Explorer. It was launched in 1953 following the conquer of the summit of Mount Everest by Sir Edmund Hillary and Tenzing Norgay and it has since been at the side of explorers, mountaineers and scientists that took it to the most forgotten parts of our world in search of the unknown. The watch is 100m water resistant, comes only in a 36mm case in steel or steel and yellow gold, and shares the movement 3230 with the other no-date watches in this guide. However, it is different from all the others because of the dial, with the iconic 3, 6, and 9 layout and the Mercedes hands, typical of the professional line.
Professional – Millgauss

The 50s were a period of trembling scientific innovation that saw engineers and technicians exposed to great magnetic fields that could affect the timekeeping capabilities of a mechanical watch. In response to this problem, Rolex introduced the Millgauss in 1956 which was a technical watch designed to withstand magnetic interference up to 1000 Gauss thanks to a shield inside the case made of ferromagnetic alloys, which protects the movement from magnetic fields, as a Faraday cage. Still today, the Maison continues to be a partner of CERN in Geneve supporting scientific conferences and events. Today the watch is available in a polished 40mm oyster case with 100m water resistance, with either a blue or black dial, a particular green shaded glass and is powered by the 3131 movement. Finally, it is characterized by a second hand that is shaped like a lightning, as a reference to the original model.
Professional – Air King

The last watch of this small guide is the Air King, that was presented in 1958 as a homage to the golden era of aviation during the 30s. If the Explorer was an evolution of the Oyster Perpetual dedicated to mountaineers and explorers, the Air King is a variation that takes inspiration from the feats of English aviator Charles Douglas Barnard, which set many flying records. Today the Air King features a 40mm oyster case, waterproof to 100m, it’s powered by the 3230 movement and it is the only one in this list that has crown protection offered by the steel case. The dial resembles two cockpit instruments created by Rolex for the Bloodhound Super Sonic Car Project, a car powered by a turbojet engine, and it is characterized by a yellow Rolex crown and a green “Rolex” writing, that is matching the green second hands.


With this article, we hope we’ve made clear for you which are the main differences among the Rolex time-only lineup. Rolex has always targeted its watches to some specific people, you can see it clearly in the famous “if you were…” adverts from the 70s and 80s where every watch model was advertised in connection with a place or activity that would better represent it. It comes to mind the Datejust paired with the Palais des Nations in Geneva, the Explorer coupled with the ascension of Mount Everest or the Day-Date seen at the wrist of a USA president. This gives you an idea of what you can find behind a watch, of its heritage and ultimately of what you find more in your wheelhouse to choose as your next companion over time.