ROLEX SERIAL NUMBER TIMELINE

Before 1987 -  Serial number consisted of between 5 to 7 digits.

1987 - Rolex added a letter at the beginning of a serial number that consisted in 6 digits.

2005- Rolex started engraving the cases serial number on the inside edge of the case at the 6 o'clock position.

2010-  Rolex began engraving its watches by using randomized identifying numbers rather than using a sequence numbering system.

At the present time, Rolex features 8 digits instead of 7 digits.

The Spirit Of The Rolex Sky-Dweller

The Rolex Sky-Dweller was inspired by an astronomical phenomenon called "Saros", which consists of a planetary mechanism of the cyclical alignment of the Sun, Earth and Moon. In addition, this timepiece has 14 ingenious Rolex patents. One of those patents is the second time zone together with an annual calendar 30-31 day months.
Such is the spirit of a Rolex Sky-Dweller watch. In the picture below you can see the various versions of this fantastic and elegant Rolex wristwatch.

BEZEL COMPARISON BETWEEN ROLEX GMT II CERAMIC VS GMT II NON-CERAMIC

One of the most distinguish features of the Rolex GMT is the 24 hour bezel, which is used to measure different time zones. The bezel of the GMT II non-ceramic uses a Click-Spring to hold the bezel in its place. On the other hand, the bezel on the GMT II ceramic rotates on three ball bearings. The GMT II ceramic bezel clicks in one-hour jumps, rather than in minutes as the GMT II non-ceramic.

Rolex GMT II Ceramic Bezel

Rolex GMT II Non-Ceramic in a Rubber B Watch Band