Another notable improvement to the collection with the arrival of Ref. 16750 is the increase in depth rating from 50 to 100 meters. 16750 has an increased depth rating from 50 to 100 meters. The watch also features the old-fashioned acrylic crystal – the sapphire made its GMT debut in 1982 with the first GMT-Master II ref. 16760. sapphire made its GMT debut in 1982 with the first GMT-Master II ref. 16760.  
Rolex debuted the GMT in 1982 with the first GMT-Master II ref. 16750 with a three-link Oyster bracelet and a five-link Jubilee bracelet with tritium as the luminous material on the dial. Finally, the bezel features a red and blue Pepsi insert or all-black, much like the stainless steel Submariner produced in the same era.
Here’s where things get interesting. Rolex originally released the Ref. 16750 with a matte dial and painted hour markers. This dial variation is much rarer than the glossy dial GMT, especially considering that many of the original matte dials have long since been replaced in routine maintenance. Rolex switched to a glossy dial in the mid-1980s, decorated with white gold-encrusted three-dimensional hour markers. Some of the glossy dials produced by replica Rolex during this period had defects in the finish that caused them to crack, a process known in watch collecting circles as “cracking.” These dials are now affectionately known as “spider dials” and are highly collectible, as Rolex replaced many during routine repairs and service.
The “cracks” on a spider dial are made up of tiny cracks in the glossy lacquer. If you look closely at the dial, you will see that it does not affect the white text. It may be hard to see at first, but the spider pattern in the shine is most visible when the dial is tilted and viewed in bright light. It didn’t take Rolex long to recognize this defect and eventually replace the original lacquer material.
Rolex’s notoriously high standards of quality mean that the company cannot consciously allow watches with spider dials to leave the repair facility without a new, flawlessly lustrous dial. For some, this is good news, as not every Rolex collector is a fan of this defect. However, some see it as one of the few quirky and rare instances where fake Rolex makes a mistake on an important part of one of its most iconic timepieces.
For this reason, some collectors will pay more than “normal” Ref. 16750s for a spider dial. At the same time, finding such rare dials at prices comparable to models without them remains entirely possible. The GMT-Master 16750 is a highly prized collector’s item because of its relatively short production run.