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The Encyclopedia of Horology

Wristwatch · Diving watch

Doxa Sub 300T Professional Wristwatch

Partially verified

This Doxa Sub 300T Professional is a men's wristwatch from the 1970s, produced during the period of Synchron ownership. The watch features an orange dial and a 42mm stainless steel case. It is equipped with a unidirectional stainless steel bezel, which retains its original orange enamel markings and a tritium luminous pearl at the 12 o'clock position. The timepiece is fitted with an original Doxa-signed "beads of rice" stretch bracelet that includes a ratcheting micro-adjust extension clasp. The dial displays tritium hour markers and hands with a creamy yellow patina. The movement's internal specifications are not documented, though the auction description reports that the watch is keeping time. The crown is an aftermarket replacement.

Front view of the Doxa Sub 300T Professional on its original beads of rice bracelet.
Front view of the Doxa Sub 300T Professional on its original beads of rice bracelet. — Craft & Tailored. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
craftandtailored.com
Category
Wristwatch · Diving watch
Maker / attribution
Doxa
Reference
Sub 300T
Catalogue / lot identifier
DXPRO300T
Source-reported date
1970s
Source-reported place
Switzerland

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 Bezel

The Doxa Sub 300T features a 42mm stainless steel case that the auction description reports has undergone light polishing in the past. The case retains its original form and dimensions with minor signs of wear.

The unidirectional stainless steel bezel remains in condition described as stunning, retaining its orange enamel and the tritium pearl located at the 12 o'clock position. The crown is unsigned and is considered an early replacement, while the original mineral glass crystal remains clean without visible wear.

Evidence for this section
  • “The excellent case has seen only light polishing in the past”
  • “The stainless steel unidirectional bezel is in stunning condition”
  • “The unsigned crown is believed to be an early replacement.”

Dial and Hands

The watch displays a high-visibility orange Professional dial. Under magnification, the surface exhibits light bubbling. The hour markers are applied with tritium lume that has acquired a creamy yellow patina over time.

Inspection under U.V. light shows no degradation of the lume on the dial indices or the matching hands. The dial includes a date aperture positioned at the 3 o'clock marker.

Evidence for this section
  • “The high visibility orange Professional dial is in beautiful vintage condition and displays some light surface bubbling”
  • “The tritium lume plots have taken on a satisfying creamy yellow patina”
  • “The original tritium hands match the dial perfectly and display no degradation under U.V. light inspection.”

Bracelet and Provenance

This watch is paired with an original Doxa-signed stainless steel "beads of rice" stretch bracelet. The clasp incorporates a ratcheting micro-adjust extension mechanism designed for use with diving suits. The bracelet shows some degree of stretch due to age but fits a 7.5-inch wrist.

The watch dates to the "Synchron Era," a period in the late 1960s and 1970s when the Doxa brand was held by Synchron. This era focused on producing durable timepieces for the burgeoning recreational diving market in the United States and Europe.

Evidence for this section
  • “The original Doxa signed "bead of rice" stretch bracelet features a unique ratcheting micro-adjust divers extension within the clasp”
  • “Synchron bought Doxa in the late 1960s”
  • “The second-generation or “Synchron Era" as many refer to it, was aimed to be the watch of choice for the emerging recreational diving community.”

Open research questions

  • What is the specific movement caliber used within this Synchron-era reference?
  • Does the current movement show specific internal Synchron-era stamps or engravings?

Source evidence

Recorded claims and source quotations for Doxa Sub 300T Professional Wristwatch
FieldSource-reported valueSource quotation
BrandDOXA“Brand DOXA”
ModelSub 300T Professional“Style Sub 300T”
Production Period1970s“1970s DOXA Sub 300T Professional (Synchron Era)”
Case MaterialStainless Steel“Material Stainless Steel”
Dial ColorOrange“Dial Orange”
Case Diameter42mm“Millimeters 42”
Bracelet TypeDoxa "Beads of Rice" Micro-Adjust Stretch Bracelet“Bracelet Doxa "Beads of Rice" Micro-Adjust Stretch Bracelet”
CrownUnsigned“The unsigned crown is believed to be an early replacement.”

Visible details

  • Orange dial with tritium indices
  • Unidirectional bezel with numerical markings
  • Stainless steel case with beads of rice bracelet
  • Date aperture at the 3 o'clock position

Research qualifications

  • Unsigned crown is believed to be an early replacement
  • Service history is unknown
  • Dial exhibits light surface bubbling visible only under loupe

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

Consulted source

ساعت مچی DOXA Sub 300T Professional دوره Synchron

Reviewed 2026-11-02 · Record 5cf327f902

Terms in this record

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

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