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The Encyclopedia of Horology

Wristwatch · Diver's wristwatch

DOXA Sub 300 'No-T' Professional

Partially verified

This Doxa Sub 300 'No-T' Professional is a dive watch from 1967, the first year of the model's production. The watch features a 42.5mm steel cushion case with an acrylic crystal and a unidirectional decompression timing bezel. The dial is orange and marked 'Professional'. The movement is an automatic-winding ETA caliber. This specific example is identified as a thin-cased 'No-T' variant, produced for only one year. The watch is supplied on an 'expandro' beads-of-rice bracelet featuring a Doxa-signed ratcheting clasp. The caseback is embossed with a sailing ship motif. According to the provided information, the dial of this example has undergone professional re-luming. The design incorporates features intended for professional diving, including a luminous oversized minute hand and a bezel engraved with US Navy no-decompression dive timing marks.

Front view of the Doxa Sub 300 'No-T' Professional on an 'expandro' beads-of-rice bracelet.
Front view of the Doxa Sub 300 'No-T' Professional on an 'expandro' beads-of-rice bracelet. — Analog:Shift. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
shop.analogshift.com
Category
Wristwatch · Diver's wristwatch
Maker / attribution
DOXA
Reference
Not recorded
Catalogue / lot identifier
AS08292
Source-reported date
1967
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 Dial Design

The watch features a 42.5mm stainless steel cushion-shaped case paired with an acrylic crystal. The caseback displays a sailing ship motif. The bezel is constructed of steel and provides unidirectional movement for timing dives, specifically engraved with US Navy no-decompression dive timing marks.

The orange dial, identified by the 'Professional' nomenclature, is a primary feature of this model. The hands include an oversized minute hand intended for improved visibility under water. The vendor reports that the dial has been subject to a professional re-luming process.

Evidence for this section
  • “42.5mm steel 'cushion' case with an acrylic crystal”
  • “steel decompression/timing bezel”
  • “'sailing ship' caseback”
  • “the arguably prototypical orange dial — which in this case — has been professionally re-lumed.”

Movement and Bracelet

The watch is equipped with an automatic-winding movement produced by ETA. This movement is described as robust and proven, suited for the intended use of the watch as a diving instrument.

It is fitted with a beads-of-rice 'expandro' bracelet. This bracelet includes a ratcheting clasp which is signed by Doxa, allowing for adjustment to the length of the band.

Evidence for this section
  • “Powered by a robust and proven automatic-winding ETA movement”
  • “fitted to a correct beads-of-rice 'expandro' bracelet with a DOXA signed ratcheting clasp.”

Historical Context and Attribution

This watch dates to 1967, which is identified as the first year of production for the Sub 300 series. The 'No-T' nomenclature refers to a thin-cased variant of the model that was manufactured for a single year.

The series is credited with introducing several innovations to the diver watch category, including the unidirectional bezel with no-decompression markings and the expanding bracelet design.

Evidence for this section
  • “The first generation of the model, introduced in 1967”
  • “orange-dialed 'Professional' model from the first year of production, 1967, with a so-called 'No-T' thin cased version produced only for one year.”
  • “the unidirectional bezel with the US Navy's no-decompression dive timing marks engraved, the expanding bracelet, and an oversized luminous minute hand.”

Open research questions

  • What is the specific ETA movement caliber contained within this case?
  • Does the caseback serial number match known production batches for the 1967 'No-T' variants?

Source evidence

Recorded claims and source quotations for DOXA Sub 300 'No-T' Professional
FieldSource-reported valueSource quotation
MakerDOXA“Vendor: DOXA”
ModelSub 300 'No-T' Professional“DOXA Sub 300 'No-T' Professional”
Year of production1967“first year of production, 1967”
Case diameter42.5mm“42.5mm steel 'cushion' case”
Movement typeAutomatic-winding ETA“robust and proven automatic-winding ETA movement”
Bracelet typeBeads-of-rice 'expandro'“correct beads-of-rice 'expandro' bracelet”
Dial colorOrange“orange-dialed 'Professional' model”
Caseback detailSailing ship“'sailing ship' caseback”

Visible details

  • The orange dial displays the 'Professional' designation and luminous markers.
  • The bezel includes markings for decompression depths in feet.
  • The case exhibits a cushion-shaped profile in stainless steel.
  • The bracelet is a beads-of-rice style link configuration.

Research qualifications

  • The dial has been professionally re-lumed, altering the original factory condition.
  • The precise movement caliber reference is not specified beyond 'ETA'.
  • The 'No-T' designation is an industry-derived term for this specific production run.

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

Consulted source

ساعت غواصی DOXA Sub 300 'No-T' Professional مدل ۱۹۶۷

Reviewed 2026-11-02 · Record 3ae1423ff5

Terms in this record

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

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