amanico delves into the intriguing mystery of Rolex and Tudor case backs marked 'VI 66', found on vintage Submariners and Explorer 1016s. This post explores whether these markings are typos, a unique dating system, or something more enigmatic, inviting the community to unravel a fascinating piece of horological history.
VI 66 Rolex Case Backs
Evil's watch, Number of the Beast, Bad Typo, existing watches?
One thing is certain: These case backs existed, as some can be found on Vintage Submariners ( Tudor AND Rolex ) as well as on the Explorer 1 of the moment, the 1016.
The 1016: ( Picture to be credited to Jacek ). Three observed pieces in the 1 499 xxx / 1 504 xxx range.
The Rolex Submariner ( 5513 and 5512 ) with serial numbers from 1 499 xxx to 1 551 xxx ( which cannot be seen as a start and an end, but which means that we are somewhere in this batch ).
Tudor 7928:
( Credit pictures of the 5513 and 7928: Jatucka ).
I am not sure this special feautre existed on other Rolex / Tudor watches, at least I didn't find any evidence of that.
The question remains unanswered, though:
Is VI 66 a bad typo, an axception to the datation system at Rolex ( month of the year instead of 1st to Fourth Quarter of the year ) or intervention of the Beast?

Best,
Nicolas
About the Rolex Explorer Ref. 1016
The reference 1016 is a notable iteration of the Explorer model, recognized for its robust design and clear legibility. It represents a period of consistent design language for the Explorer line, maintaining core aesthetic principles while incorporating incremental technical refinements. This reference is particularly distinguished by its long production run, allowing for various dial and case nuances across its manufacturing years.
This reference features a 36 mm stainless steel Oyster case, providing a durable and functional enclosure for the automatic caliber 1570 movement. The movement offers a power reserve of approximately 42-48 hours. The watch is fitted with an acrylic crystal, contributing to its vintage appeal and period-correct specifications. Water resistance is rated at 100 meters, underscoring its design for practical use.
For collectors, the reference 1016 holds interest due to its enduring design and the variations found within its production. Different dial types, such as gilt and matte, are observed, each appealing to specific collecting preferences. Its straightforward time-only display and tool-watch aesthetic make it a representative example of the Explorer series' foundational principles.
Specifications
- Caliber
- 1570
- Case
- Stainless steel
- Diameter
- 36 mm
- Dial
- Black
- Water Resist.
- 100m
- Crystal
- Acrylic
About the Rolex Submariner Ref. 5512
Rolex Submariner Reference 5512
The Submariner reference 5512 represents Rolex's no-date variant within the Submariner series. Distinguished by its clean dial layout without date complication, this reference was produced from 1962 to 1989, spanning nearly three decades of manufacturing.
The 40mm stainless steel case houses either caliber 1560 or 1570 automatic movements, providing 42-48 hours of power reserve. The watch features a black dial, unidirectional rotating bezel with aluminum insert, and acrylic crystal. Water resistance extends to 200 meters, with the watch fitted to a stainless steel bracelet.
This reference appeals to collectors seeking the fundamental Submariner aesthetic without date functionality. The extended production period and dual caliber usage create multiple variations within the 5512 designation. The no-date configuration offers symmetrical dial proportions that attract purists within the collecting community.
Specifications
- Caliber
- 1560/1570
- Case
- Stainless steel
- Diameter
- 40 mm
- Dial
- Black
- Water Resist.
- 200m
- Crystal
- Acrylic
About the Rolex Tudor Submariner Ref. 7928
The Tudor Submariner reference 7928 represents a significant evolution within the brand's dive watch lineage, succeeding earlier references and establishing many of the design codes that would define future Tudor Submariners. Positioned as a robust and accessible alternative to its Rolex counterpart, the 7928 was widely adopted by military forces and civilian divers alike, solidifying Tudor's reputation for producing reliable tool watches.
This reference typically features a 39mm stainless steel case, often characterized by either pointed crown guards (PCG) or square crown guards (SCG), depending on the production period. It is powered by the ETA-based Caliber 390, a self-winding movement known for its durability. Early examples may feature gilt dials and 'smiley' self-winding text, while later versions transitioned to matte dials with white printing. The bidirectional rotating bezel is fitted with an aluminum insert, often featuring a red triangle at 12 o'clock.
For collectors, the 7928 is highly sought after due to its historical significance and the wide array of variations, including different crown guard styles, dial types (gilt, matte, underlined), and military or retailer-signed examples. Its robust construction and classic design ensure its continued relevance in the vintage watch market, appealing to those who appreciate its utilitarian origins and distinct aesthetic.
Specifications
- Caliber
- Caliber 390
- Case
- Stainless Steel
- Diameter
- 39mm
- Dial
- Black
- Water Resist.
- 200m
- Crystal
- Plexiglass
About the Rolex 16660 Ref. 16660
The Rolex Sea-Dweller reference 16660, often referred to as the "Triple Six," represents a significant transitional model within the Sea-Dweller lineage. It was the first Sea-Dweller to incorporate a sapphire crystal, a crucial upgrade that enhanced its pressure resistance and durability compared to its plexiglass predecessors. This reference also marked the introduction of a larger helium escape valve, further solidifying its professional dive watch credentials and distinguishing it from earlier iterations. It bridges the gap between the vintage four-digit references and the more modern five-digit models.
This reference features a 40 mm stainless steel Oyster case, designed for extreme depths. It is powered by the automatic Caliber 3035, a robust movement known for its reliability and quick-set date function. The watch is equipped with a sapphire crystal, contributing to its impressive water resistance of 1220 meters (4000 feet). The unidirectional rotating bezel allows for precise timing of immersion, and the Oyster bracelet ensures secure wear during demanding activities.
For collectors, the 16660 is notable for its transitional characteristics, offering both vintage appeal with its matte dial variants in early production and the enhanced technical specifications of later models. It appeals to those seeking a robust tool watch with historical significance, representing a key evolutionary step in Rolex's professional dive watch development. The reference is recognized for its engineering advancements and its role in the continuous refinement of the Sea-Dweller series.
Specifications
- Caliber
- Cal. 3035
- Case
- Stainless steel
- Diameter
- 40 mm
- Dial
- Black
- Water Resist.
- 1220m (4000ft)
- Crystal
- Sapphire crystal