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Zenith Chronomaster Sport El Primero 3600 41mm
Ref. 03.3100.3600/21.M3100
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Stepping up in the same dial colour
The El Primero calibre has a particular place in watchmaking history: Zenith introduced it in 1969 as one of the first automatic chronograph movements, and its 36,000 vph frequency — twice the rate of most contemporaries — was the reason it could time in tenths of a second rather than fifths. The Chronomaster Sport is where that movement gets the treatment it warrants: a ceramic bezel graduated to tenths, a case designed around the integrated bracelet, and the three-register dial layout that has been the house signature since the original. The tri-colour subdials — grey, anthracite and blue against the matte black lacquer — are one of those details that read as a pattern rather than a spec at a glance, but reward a closer look every time the light changes. At 13.6mm the case is not thin, but it sits honestly for what it contains: a 311-part movement with a column-wheel, a hacking function and 60 hours of reserve, visible in full through the exhibition caseback.
- Reference
- 03.3100.3600/21.M3100
- Brand
- Zenith
- Collection
- Chronomaster
- Case size
- 41mm
- Case thickness
- 13.6mm
- Case material
- Stainless steel
- Case shape
- Round
- 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
- Buckle
- Lume
- Super-LumiNova
- Retailer
- Mappin & Webb
Additional specifications
- Power reserve
- 60 hours
- Warranty
- 2 years
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 6 collections
This watch appears in the Zenith Chronomaster range (19), Back in Stock (4,007), Stainless Steel Watches (2,833), Automatic Watches (1,417), Chronograph Watches (1,131) and Sports Watches (667).
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
- Sits in the lower half of Zenith's range as we list it
Zenith Chronomaster Sport El Primero alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | 03.3100.3600/21.M3100 | 103926 | G0A43001 |
|---|---|---|---|
| Price | £10,400 | £9,400 | £11,400 |
| Case size | 41mm | 41mm | 42mm |
| Water resistance | 100m | 100m | 100m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Stainless steel bracelet | Stainless steel bracelet | Leather strap |
| Power reserve | 60 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.
Cheapest place to buy
Mappin & Webb is the only UK retailer we track stocking this reference, so there is nothing to compare it against today.
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