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The Encyclopedia of Horology

Wristwatch · Two-time zone wristwatch

Arnold & Son Instrument DBG Equation GMT

Partially verified

This Arnold & Son Instrument DBG Equation GMT wristwatch, reference 1DGAS.S01A.C121S, is a manual-winding stainless steel timepiece. Featuring a 44 mm diameter round case, it is equipped with the A&S 1209 caliber, which incorporates a double barrel and dual gear train system, each with its own escapement and balance. The watch provides two separate time displays and includes a 24-hour GMT indication on a subsidiary dial positioned at 12 o'clock. The dial is light-grey and silver opaline with radial Roman and Arabic numerals. This example is a numbered edition, marked as No. 028, and is accompanied by an original fitted box, certificate of origin, and an instruction booklet. The watch is worn on a black crocodile leather strap with a stainless steel buckle. The movement is adjusted to five positions and features a sapphire-crystal exhibition case-back secured by six screws.

The Arnold & Son DBG Equation GMT watch shown with its original fitted box and documentation.
The Arnold & Son DBG Equation GMT watch shown with its original fitted box and documentation. — Antiquorum. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
catalog.antiquorum.swiss
Category
Wristwatch · Two-time zone wristwatch
Maker / attribution
Arnold & Son
Reference
1DGAS.S01A.C121S
Catalogue / lot identifier
169
Source-reported date
circa 2015
Source-reported place
Switzerland
Source-reported serial
16.1.1.01

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

Dial and Case Construction

The watch features a 44 mm stainless steel round case with a water-resistant design. The exhibition back is secured by six screws, revealing the movement. The dial is executed in light-grey and silver opaline, incorporating a combination of radial Roman and Arabic numerals.

The display architecture manages two distinct time zones, each powered by an independent gear train and barrel, with a subsidiary dial located at 12 o'clock providing a 24-hour indication for the GMT complication.

Evidence for this section
  • “Stainless steel, manual-winding, round-shaped, large gentleman’s wristwatch, water-resistant with sapphire-crystal case-back screwed by six screws”
  • “light-grey and silver opaline colour dial with radial Roman and Arabic numerals”

Movement Architecture

The caliber A&S 1209 is a manual-winding movement featuring a double barrel and a double escapement configuration. This arrangement allows the two time displays to operate independently, preventing energy drain from one function from impacting the accuracy of the other.

The movement is adjusted to five positions and possesses a 40-hour power reserve. The engineering is designed to allow the housing of distinct technical characteristics for separate complications within a single movement.

Evidence for this section
  • “Two separate time displays, each driven by its own barrel and gear train with its own escapement and balance”
  • “Caliber A&S 1209, two barrels, adjusted to five positions (40 hours)”

Provenance and Documentation

The watch is identified as part of a limited, numbered edition, specifically unit number 028. The object is provided with its original fitted box, a certificate of origin, and an instruction booklet.

The auction description reports the watch as being in excellent condition, grading the case and dial as new. Authenticity and signature are confirmed on the dial, case, and movement.

Evidence for this section
  • “Limited Edition numbered edition, No. 028”
  • “Accessories original fitted box, certificate or origin, instruction booklet”

Open research questions

  • What is the specific date of the individual watch's manufacture within the circa 2015 timeframe?
  • What are the precise manufacturing limitations of the 'numbered edition' for this reference?

Source evidence

Recorded claims and source quotations for Arnold & Son Instrument DBG Equation GMT
FieldSource-reported valueSource quotation
MakerArnold & Son“Arnold & Son, London and La Chaux-de-Fonds”
Reference1DGAS.S01A.C121S“Ref. 1DGAS.S01A.C121S”
Movement CaliberA&S 1209“Caliber A&S 1209, two barrels, adjusted to five positions (40 hours)”
Case Number16.1.1.01“Case No. 16.1.1.01”
EditionNo. 028“Limited Edition numbered edition, No. 028”
Case Diameter44 mm“Diameter 44 mm.”
Case MaterialStainless steel“stainless steel”

Visible details

  • Dual balances and escapements visible on the dial side
  • Light-grey and silver opaline dial with Roman and Arabic numerals
  • Exhibition case-back showing the movement bridge architecture
  • Black crocodile leather strap with Arnold & Son logo

Research qualifications

  • The exact production year is provided as 'circa 2015'
  • Condition is stated as 'As new' by the auction description

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

Consulted source

Arnold & Son - Ref. 1DGAS.S01A.C121S, double barrel and escapement, Two-time zone, GMT 24-hour indication; “Instrument”, “DBG Equation GMT”; numbered edition; stainless steel

Reviewed 2026-10-26 · Record 2c340104e5

Terms in this record

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

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