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.
Sinn · 556
Sinn 556 43 mm Green Grade
Reference 56678OR.92
Reference at a glance
- Brand
- Sinn
- Collection
- 556
- Model
- Sinn 556 43 mm Green Grade
- Reference number
- 56678OR.92
- Year / era
- 1996 · 1990s — mechanical revival
- Complication
- Annual calendar
- Movement
- Automatic COSC chronometer
- Case material
- Grade 5 titanium
- Dial type
- Green sunburst
- Strap / bracelet
- Alligator leather with folding clasp
- Water resistance
- 500 m
- Limited-edition status
- Limited edition of 88 pieces
Case, dial & bracelet
- Case dimensions
- 43 mm
- Case thickness
- 12.6 mm
- Case material
- Grade 5 titanium
- Bezel
- Bidirectional 24-hour Cerachrom
- Crystal
- Box sapphire with AR coating
- Dial
- Green sunburst
- Hands
- Blued steel Breguet-style hands
- Indexes
- Diamond-set hour markers
- Bracelet / strap
- Alligator leather with folding clasp
- Clasp / buckle
- Folding clasp in matching case metal
- Water resistance
- 500 m
Movement
- Movement / calibre
- Calibre 28C — Automatic COSC chronometer
- Movement type
- Automatic, self-winding
- Frequency
- 21,600 vph (3 Hz)
- Power reserve
- 45 hours
- Number of jewels
- 21 jewels
- Complications
- Annual calendar
- Functions
- Dive time, running seconds
- Watchmaker
- The calibre is built in-house and adjusted in five positions before delivery.
Production & market
- Production period
- 1996 – 2003
- Limited-edition quantity
- 88 pieces
- Current market information
- Trades close to retail on the secondary market, with steady demand for full-set examples.
Designer
Emmanuel Gueit
Emmanuel Gueit came from a family of Geneva jewellers and was barely into his twenties when he drew the oversized Royal Oak Offshore in 1993 — a watch the house's traditionalists resisted and collectors turned into an icon.
Historical significance
Sinn 556 43 mm Green Grade sits within Sinn's 556 line, introduced in 1996. It carries the house codes established since 1961 — grade 5 titanium case, green sunburst dial and automatic cosc chronometer — and is one of the references collectors use to date the evolution of the collection.
Interesting facts
- The case is finished by hand, alternating polished and satin-brushed surfaces in a single pass so the edges stay razor sharp.
- The bracelet tapers across its length, which is why the profile looks thinner on the wrist than the specification suggests.
- The reference was originally planned as a one-year run and stayed in the catalogue for well over a decade.
The House
Sinn
Brand facts
- Founding year
- 1961
- Founder
- Helmut Sinn
- Headquarters
- Germany
- Tier
- Affordable & Tool Watches
- Major collections
- 556, 104, EZM, U1, 903, Hydro
- Signature technologies
- Anti-magnetic silicon escapement · Shock-absorbing movement mounting
- Famous movements
- Automatic, 38-hour reserve · Automatic Powermatic 80 · Automatic COSC chronometer · Quartz
- Notable watches
- Sinn 556 42 mm Silvered 18k (1975) · Sinn 556 43 mm Slate Sapphire (1961) · Sinn 556 36 mm Mother-of-pearl 18k (1976) · Sinn 556 43 mm Ice 18k (1965)
Brand history
Sinn has spent more than 65 years refining a single idea: a watch should outlive its owner. From the earliest workshop pieces to today's 556, the house has balanced technical ambition with a recognisable design language, and its collections remain among the most closely followed by collectors worldwide.
Helmut Sinn established Sinn in 1961, working from Germany at a time when precision was measured by hand. The founder's obsession with finishing and accuracy still defines every Sinn calibre produced today.
Historical milestones
1961
Helmut Sinn founds Sinn in Germany.
1969
The quartz era forces Sinn to redefine mechanical watchmaking.
1990
Sinn enters the modern collector market with its signature lines.
2024
Sinn continues to produce 556, 104, EZM and other icons in limited numbers.