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Scan for outdated or missing drivers - takes under a minuteDriver Scan →Repair Windows errors before they cause bigger problemsFix Now →The Zenith Defy El Primero 21 uses two independent regulating systems: one runs the watch’s time display at 5 Hz, while a second runs the chronograph at 50 Hz. Zenith says the faster chronograph system enables a 1/100-second display; it is a description of the watch’s mechanism and indication, not an independent real-world accuracy test. The documented titanium and carbon models share core movement specifications, but differ in materials and supplied strap or bracelet.
How does the Defy 21 measure 1/100th of a second?
The watch separates ordinary timekeeping from chronograph timing instead of asking one regulating system to do both. Zenith describes the time display as running at 5 Hz, or 36,000 vibrations per hour, and the chronograph as running at 50 Hz, or 360,000 vibrations per hour. The latter high frequency supports the hundredths-of-a-second indication.
In Zenith’s 2017 launch description, the chronograph’s central hand completes one turn around the dial each second. Zenith also described a double-chain structure with two regulators and said the 50 Hz escapement emits a “pleasant ‘buzzing’.” That is the manufacturer’s descriptive language, not a measured sound level or a claim about every wearer’s experience. See Zenith’s 2017 launch article.
The documented titanium and carbon references use the automatic El Primero 9004 movement and list approximately 50 hours of power reserve. These are published specifications for those references, not a guarantee that every Defy 21 edition has identical internals. Zenith’s technical sheets provide the details for the brushed titanium reference and the carbon reference.
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Titanium vs. carbon: what differs?
The two published technical sheets describe 44 mm cases, 14.50 mm thickness, 10 ATM water resistance, an openworked dial and a transparent sapphire caseback with anti-reflective treatment on both sides. The main practical differences in these examples are the case and the supplied wrist hardware.
| Reference | Case and dimensions | Movement and reserve | Other listed details |
|---|---|---|---|
| 95.9000.9004/78.M9000 | Brushed titanium; 44 mm diameter; 14.50 mm thick | Automatic El Primero 9004; approximately 50 hours | 10 ATM; openworked dial; titanium bracelet; sapphire crystal with anti-reflective treatment on both sides; transparent sapphire caseback. The titanium sheet lists 293 components and 53 jewels. |
| 10.9000.9004/96.R921 | Carbon; 44 mm diameter; 14.50 mm thick | Automatic El Primero 9004; approximately 50 hours | 10 ATM; openworked dial; rubber strap; titanium-and-carbon folding clasp; sapphire crystal with anti-reflective treatment on both sides; transparent sapphire caseback. Component and jewel counts are not stated in the cited carbon sheet. |
Those dimensions and water-resistance figures belong to the named references. They should not be assumed for every Defy 21: Zenith has made other editions, and specifications can vary. Check the reference number and its own technical sheet before comparing fit, materials or water resistance.
What about special editions?
The 2017 Only Watch Defy El Primero 21 was a unique charity-auction piece, not a standard production option. Zenith described it with a 44 mm black DLC titanium case, yellow details, a 1/100-second chronograph and the double-chain, two-regulator structure. Its auction-specific status matters when comparing listings with regular references. Details appear in Zenith’s Only Watch 2017 announcement.
Zenith announced the carbon model as a distinct iteration in 2019. That historical launch does not establish whether a particular reference is currently being produced or stocked.
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Is the Zenith Defy El Primero 21 still available?
Availability depends on market and exact reference. On 2026-10-07, Zenith’s Netherlands collection page displayed €15,600 and marked the listing sold out; its United Kingdom page displayed £13,500 and marked it sold out. The United States page displayed $14,500, but did not establish the availability of every historical reference. These are regional page listings, not verified transaction prices or a universal current offer.
Check the relevant official regional page for the current listing, then ask an official boutique or authorized retailer about the exact reference. A collection page or marketplace listing alone does not establish stock, seller authorization, warranty coverage or service terms. The three regional pages are Zenith’s Netherlands collection page, United Kingdom collection page and United States collection page.
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Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
