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Zenith Defy Skyline Chronograph 42mm Mens Watch Black Interchangeable Strap
Ref. 03.9500.3600/21.I001
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Stepping up in Zenith's range
Defy Skyline Chronograph Skeleton 42mm Mens Watch Black Interchangeable Strap£14,500
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Chronomaster Sport 41mm Mens Watch Grey£16,100
The El Primero has been Zenith's defining movement since 1969, when it became the first automatic chronograph calibre to run at 36,000 vibrations per hour. The 3600 variant pushes that idea further: at 5 Hz the central chronograph hand completes a full sweep every ten seconds, making the 1/10th-of-a-second scale on the inner flange genuinely readable rather than decorative. That precision sits inside an octagonal case with a twelve-sided faceted bezel — an architectural form the Defy line has used to signal that it belongs to the sports end of what Zenith makes. The black sunray dial is engraved with Zenith's four-pointed star across its full surface, which means the pattern shifts as the light moves rather than sitting flat. The three sub-dials follow the classic El Primero layout, and the rhodium-plated hands carry C1 lume, so the watch reads well after dark without depending on it. The exhibition caseback is worth knowing about: it exposes the movement fully, and at 12.7mm the case is slim enough that this does not read as a watch built around its own bulk. The quick-change mechanism means the included rubber strap swaps in without tools, which is a practical detail on a watch rated for the water.
- Reference
- 03.9500.3600/21.I001
- Brand
- Zenith
- Collection
- Defy
- Case size
- 42mm
- Case thickness
- 12.7mm
- Case material
- Stainless steel
- Case shape
- Octagonal
- Dial
- Black
- Crystal
- Sapphire
- Movement
- Automatic
- Calibre
- El Primero 3600
- Functions
- Chronograph, Date, Small seconds
- Water resistance
- 100m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Silver
- Clasp
- Folding clasp
- Lume
- Super-LumiNova
- Retailer
- Goldsmiths
Additional specifications
- Power reserve
- 60 hours
- Strap
- Interchangeable
Learn more about Zenith
Georges Favre-Jacot founded Zenith in Le Locle in 1865, aged twenty-two, with an idea that was radical for the Swiss industry: bring every trade needed to make a watch — movement, case, dial, hands — under one roof and one management. The integrated manufacture was largely his invention, and the Le Locle site he built is still in use.
The approach produced results at observatory trials, where Zenith accumulated more precision awards than any other manufacture. The name itself came from a calibre Favre-Jacot considered the summit of his work.
Its defining achievement is the El Primero of 1969, developed over seven years and announced in the same year as the Heuer-Breitling consortium's Calibre 11 and Seiko's 6139. It was an integrated automatic chronograph beating at 36,000 vibrations per hour, allowing measurement to a tenth of a second — a frequency almost nothing else matched for decades.
It nearly did not survive. When American owners ordered the mechanical tooling scrapped during the quartz crisis, a watchmaker named Charles Vermot hid the plans, presses, and cams in a walled-off attic. When demand for mechanical chronographs returned, Zenith could restart production because of him. Rolex used the El Primero in the Daytona from 1988 to 2000.
LVMH acquired Zenith in 1999.
- 1865
- Georges Favre-Jacot founds the integrated manufacture at Le Locle.
- 1969
- The El Primero automatic chronograph debuts at 36,000 vph.
- 1975
- Charles Vermot hides the El Primero tooling from destruction.
- 1988
- Rolex adopts the El Primero for the Daytona.
- 1999
- Acquired by LVMH.
Also in 5 collections
This watch appears in the Zenith Defy range (23), Back in Stock (4,007), Stainless Steel Watches (2,833), Automatic Watches (1,417) and Chronograph Watches (1,131).
Temporarily out of stock
Goldsmiths is not currently taking orders for this reference. Last listed as available on 26 September 2026. Stock is checked nightly and this page updates when it returns.
What the specifications mean
A mechanical watch for everyday wear.
Strengths
- 100m water resistance covers swimming and watersports
- Sapphire crystal, which resists scratching
- Luminous hands and markers for low light
Zenith Defy Skyline alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | 03.9500.3600/21.I001 | 81010-11-3592-1GM | G0A49022 |
|---|---|---|---|
| Price | £12,500 | £12,600 | £12,900 |
| Case size | 42mm | 42mm | 42mm |
| Water resistance | 100m | 100m | 100m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Stainless steel bracelet | Stainless steel bracelet | Stainless steel bracelet |
| Power reserve | 60 hours | 54 hours | 50 hours |
| This watch | Closely matched | Closely matched |
Your new watch
Frequently asked questions, and things you should know about this watch
Can I swim with it?
Yes. At 100m it is rated for swimming and snorkelling, though not for diving.
Water resistance explainedWill the glass scratch?
Unlikely. Sapphire is second only to diamond in hardness and shrugs off everyday marking.
Sapphire, mineral and acrylic comparedDoes it need a battery?
No. It is automatic — the motion of your wrist winds it, and there is no cell to replace.
Quartz, automatic and solar comparedHow long does it run for when it's not worn?
About 60 hours fully wound — enough to survive a night off the wrist, but not a full weekend.
Is it a men's or women's watch?
Listed as men's.
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