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The Encyclopedia of Horology

Wristwatch · Chronograph

Rolex Daytona Ref. 16520 'Zenith'

Partially verified

This Rolex Daytona, identified as a Reference 16520 from circa 1991, is a chronograph wristwatch characterized by its white 'Inverted 6' dial. The watch utilizes the Rolex 4030 movement, which is based on a modified El Primero automatic-winding movement. Key external features include a stainless steel Oyster case equipped with a sapphire crystal and a steel tachymeter bezel. The watch is presented on its early, fully-brushed stainless steel Oyster bracelet featuring a blade-style clasp. The dial displays applied Tritium-filled indices and contrasting black sub-registers. The auction description reports the watch has been very lightly polished while retaining factory finishing, with the bezel displaying intact black paint within the engraved markings. The watch is stated to have a depth rating of 100 meters or 330 feet.

Front view of the Rolex Daytona Ref. 16520 displaying the white 'Inverted 6' dial and brushed Oyster bracelet.
Front view of the Rolex Daytona Ref. 16520 displaying the white 'Inverted 6' dial and brushed Oyster bracelet. — Oliver & Clarke. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
oliverandclarke.com
Category
Wristwatch · Chronograph
Maker / attribution
Rolex
Reference
16520
Catalogue / lot identifier
Source URL identifies the listing
Source-reported date
circa 1991
Source-reported place
Not established

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Case and Bracelet

The stainless steel Oyster case is reported to have been lightly polished previously, though it retains factory finishing. The case is matched with a stainless steel bezel that features a tachymeter scale, which the vendor notes contains fully-intact black paint within the engraved markings.

This example is equipped with an early, fully-brushed stainless steel Oyster bracelet. Unlike later designs that utilized polished center-links and a fliplock mechanism, this piece retains a blade-style clasp, described as the correct configuration for this production era.

Evidence for this section
  • “showing signs of having been very lightly previously polished, with visible factory finishing”
  • “matching steel bezel shows normal wear from age with fully-intact black paint within the engraved markings”
  • “comes fitted its correct fully-brushed stainless steel Oyster blade with a blade clasp”

Dial and Movement

The dial is finished in gloss white and features three contrasting black sub-registers. A notable detail is the 'Inverted 6' marking on the lower sub-dial. The indices are applied and filled with Tritium, which the vendor describes as being evenly patinated.

Internally, the watch is powered by the Rolex 4030 movement. This caliber is based on an outsourced El Primero movement, which underwent approximately 200 modifications by Rolex prior to its implementation in the 16xxx reference series.

Evidence for this section
  • “gloss white 'Inverted 6' dial is virtually flawless”
  • “evenly patinated applied Tritium-filled indices”
  • “performing approximately 200 modifications to the base movement”
  • “modified El Primero automatic-winding movement”

Technical Specification

The Reference 16520 utilizes a sapphire crystal, which contributes to the watch's depth rating. The vendor specifies that this model is rated for water resistance to a depth of 100 meters or 330 feet.

The 4030 movement, serving as the primary mechanical driver for the watch, was produced for a twelve-year period starting in 1988, following Rolex's decision to utilize an automatic-winding caliber for their Daytona line.

Evidence for this section
  • “Rolex also incorporated the more resilient sapphire crystals”
  • “increased depth rating guaranteed at 100m or 330ft”
  • “created the workhorse Rolex 4030 movement that was put in production for an era of 12 years”

Open research questions

  • What is the specific production serial number range for this 1991 example?
  • Does the case back include any service markings from previous ownership?

Source evidence

Recorded claims and source quotations for Rolex Daytona Ref. 16520 'Zenith'
FieldSource-reported valueSource quotation
Reference16520“Reference 16520”
Datecirca 1991“dating to circa 1991”
Movement baseEl Primero“modified El Primero automatic-winding movement”
Depth rating100m / 330ft“increased depth rating guaranteed at 100m or 330ft”
Dial featuresWhite Inverted 6 dial with Tritium indices“gloss white 'Inverted 6' dial is virtually flawless, with evenly patinated applied Tritium-filled indices”
BraceletFully-brushed stainless steel Oyster bracelet with blade clasp“comes fitted its correct fully-brushed stainless steel Oyster blade with a blade clasp”

Visible details

  • Gloss white dial with an 'inverted 6' numeral in the bottom sub-register
  • Applied indices containing Tritium luminous material
  • Stainless steel tachymeter bezel with black engraved markings
  • Fully-brushed Oyster bracelet with blade-style clasp

Research qualifications

  • The extent of previous polishing is based on the vendor's assessment
  • The specific production serial number is not provided

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

ساعت مچی رولکس Rolex Daytona Ref. 16520 'Zenith' با صفحه سفید Inverted 6

Reviewed 2026-11-02 · Record ed687addac

Terms in this record

Glossary explanations for terms named in this object’s record.

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