Front view
Dial, hands and bezel as delivered.
Case-back view
Case-back engraving and, where fitted, the sapphire display.
Movement
Calibre with its finishing and decoration.
On the wrist
Worn shot for proportion and strap drape.
Zenith · El Primero
Zenith El Primero 42 mm Slate Platinum
Reference 65009OR.28
Reference at a glance
- Brand
- Zenith
- Collection
- El Primero
- Model
- Zenith El Primero 42 mm Slate Platinum
- Reference number
- 65009OR.28
- Year / era
- 1954 · 1950s — pre-quartz mechanical era
- Complication
- Chronograph
- Movement
- In-house automatic, Superlative Chronometer
- Case material
- Platinum 950
- Dial type
- Slate grey
- Strap / bracelet
- Alligator leather with folding clasp
- Water resistance
- 100 m
- Limited-edition status
- Regular production, not a limited edition
Case, dial & bracelet
- Case dimensions
- 42 mm
- Case thickness
- 11.3 mm
- Case material
- Platinum 950
- Bezel
- Emerald-set
- Crystal
- Anti-reflective sapphire, double-domed
- Dial
- Slate grey
- Hands
- Rhodium-plated baton hands with luminous fill
- Indexes
- Applied faceted white-gold indexes
- Bracelet / strap
- Alligator leather with folding clasp
- Clasp / buckle
- Pin buckle in matching case metal
- Water resistance
- 100 m
Movement
- Movement / calibre
- Calibre 50B — In-house automatic, Superlative Chronometer
- Movement type
- Automatic with micro-rotor
- Frequency
- 25,200 vph (3.5 Hz)
- Power reserve
- 38 hours
- Number of jewels
- 37 jewels
- Complications
- Chronograph
- Functions
- Flying tourbillon, power reserve
- Watchmaker
- Assembled and regulated by a single watchmaker, who signs off the piece before casing.
Production & market
- Production period
- 1954 – 1964
- Limited-edition quantity
- Not applicable
- Current market information
- Values have stabilised after the 2022 correction; condition and box-and-papers drive the premium.
Designer
Jörg Hysek
Jörg Hysek left Rolex and Seiko's European studios to build a design practice in Geneva, giving houses such as Vacheron Constantin, Breguet, Seiko and TAG Heuer their sculptural, architecture-led cases before founding his own brand, HD3.
Historical significance
Zenith El Primero 42 mm Slate Platinum sits within Zenith's El Primero line, introduced in 1954. It carries the house codes established since 1865 — platinum 950 case, slate grey dial and in-house automatic, superlative chronometer — and is one of the references collectors use to date the evolution of the collection.
Interesting facts
- Early production dials show a slightly different minute track, and collectors pay a premium for them.
- The case is finished by hand, alternating polished and satin-brushed surfaces in a single pass so the edges stay razor sharp.
The House
Zenith
Brand facts
- Founding year
- 1865
- Founder
- Georges Favre-Jacot
- Headquarters
- Switzerland
- Tier
- Luxury
- Major collections
- El Primero, Chronomaster, Defy, Pilot, Elite
- Signature technologies
- Proprietary case-hardening and polishing · In-house hairspring production · Certified chronometer regulation
- Famous movements
- In-house automatic, Superlative Chronometer · In-house automatic, chronometer certified · In-house manual-winding · In-house automatic chronograph
- Notable watches
- Zenith El Primero 42 mm Slate Platinum (1954) · Zenith El Primero 42 mm Mother-of-pearl Ceramic (1965) · Zenith El Primero 41 mm Skeletonised Sapphire (1975) · Zenith El Primero 40 mm Silvered 18k (1995)
Brand history
Zenith has spent more than 161 years refining a single idea: a watch should outlive its owner. From the earliest workshop pieces to today's El Primero, the house has balanced technical ambition with a recognisable design language, and its collections remain among the most closely followed by collectors worldwide.
Georges Favre-Jacot established Zenith in 1865, working from Switzerland at a time when precision was measured by hand. The founder's obsession with finishing and accuracy still defines every Zenith calibre produced today.
Historical milestones
1865
Georges Favre-Jacot founds Zenith in Switzerland.
1899
Zenith earns its first international recognition for precision timekeeping.
1969
The quartz era forces Zenith to redefine mechanical watchmaking.
1990
Zenith enters the modern collector market with its signature lines.
2024
Zenith continues to produce El Primero, Chronomaster, Defy and other icons in limited numbers.