Zenith · Chronomaster · El Primero Open Power Reserve · Ref 18.2080.4021/01.C494 · new on Amazon
A window cut into the dial so you can watch it beat.
Zenith’s El Primero has run at 36,000 beats an hour since 1969; the Chronomaster Open cuts the dial away at ten o’clock so you can see the escapement doing it. This one is the 42mm case in 18k rose gold with a silver dial, a power reserve arc at six, a tachymeter and a brown alligator strap. New from an independent dealer through Amazon.
Case
42mm, 18k rose gold
Zenith Chronomaster Open Power Reserve
Movement
El Primero 4021, automatic chronograph
Zenith; Amazon table: automatic, power reserve
Beat rate
36,000 vph (5 Hz)
Zenith El Primero
Power reserve
About 50 hours, with indicator
Zenith El Primero 4021
Water resistance
100m (10 ATM)
Zenith
Strap
Brown alligator, rose gold buckle
Amazon spec table: two-piece strap, buckle
Five beats a second
Most mechanical chronographs tick at 28,800 beats an hour. The El Primero has ticked at 36,000 since Zenith launched it in 1969, which lets the chronograph hand read to a tenth of a second and is the reason the movement survived the quartz years: a Zenith watchmaker hid the tooling in an attic rather than scrap it, and Rolex bought the El Primero for the Daytona in the late 1980s.
The Open version, introduced in 2003, cuts an aperture in the dial over the balance and escapement so the five beats a second are visible. The 4021 in this watch adds a power reserve indicator, the arc at six that reads Réserve de Marche.
Gold, silver dial, blue hands
The 18k rose gold case is the dress version of the Chronomaster Open; the silver dial with rose gold markers and blued chronograph hands is the combination Zenith used for its more formal El Primeros. It is a chronograph you can wear with a suit, and at 42mm it is not a small one.
Every figure here comes from the Amazon spec table and Zenith’s published specification for the reference, not from handling the watch. The Amazon table says both automatic and manual winding; the El Primero 4021 is automatic.
Buying it new on Amazon
This unit is listed new by an independent dealer through Amazon, with Amazon’s 30-day return window on top of the dealer’s warranty; read the warranty line on the listing, because Zenith’s own warranty runs from an authorised sale.
Gold Zeniths trade below their retail price on the secondary market, which is why dealer stock like this sits on Amazon well under boutique retail. Buy it for the movement. Nothing here is investment advice.
Specs
- Reference
- 18.2080.4021/01.C494
- Case size
- 42mm
- Case material
- 18k rose gold
- Movement
- Automatic chronograph, Zenith El Primero 4021
- Caliber type
- El Primero 4021, 36,000 vph (5 Hz), column wheel, automatic
- Crystal
- Sapphire Crystal, sapphire exhibition caseback
- Water resistance
- 100m (10 ATM)
- Power reserve
- About 50 hours, with indicator
- Complications
- Chronograph, power reserve indicator, open escapement at 10 o'clock
- Origin
- Swiss Made
Specifications as published by Zenith. We research from manufacturer documentation and published sources rather than hands-on testing. Researched 2026-09-12.
Verdict
The high-beat El Primero with its escapement on show, in rose gold with a power reserve, new from a dealer.
Strengths
- El Primero 4021: 36,000 vph, column wheel, tenth-of-a-second chronograph
- Open dial over the escapement, power reserve arc at six
- 18k rose gold, silver dial, blued hands; 100m
- New, with Amazon’s return window
Trade-offs
- Gold Zeniths resell below retail
- 42mm and a busy dial; not a discreet watch
- Dealer warranty, not Zenith’s from purchase
- The Amazon table contradicts itself on winding; it is automatic
Buy it if
Someone who wants the most famous chronograph movement there is, and wants to watch it run.
Skip it if
You want a clean dial, a smaller case, or resale value.
FAQ
It runs at 36,000 beats an hour, five per second, which lets the chronograph read to a tenth of a second. It has done so since 1969 and was the movement in the Rolex Daytona from 1988 to 2000.
Sources
- Zenith Chronomaster, official collection page
- Amazon marketplace listing (new, independent dealer), read 2026-09-12
Researched and last updated 2026-09-12. We do not test watches in hand; every figure above is traceable to the manufacturer or the sources listed here.
Zenith Chronomaster El Primero Open Power Reserve (18k rose gold)
Reference 18.2080.4021/01.C494 · $10,000–$25,000
Prices and availability change; the band above is a research figure, so check the current listing.
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