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The Greubel Forsey Nano Foudroyante EWT is an experimental, 11-piece watch that combines a monopusher flyback chronograph with a flying tourbillon and a continuously running foudroyante display. Its “nano” name refers to the tiny amount of energy the mechanism uses—not components made at nanometre scale.
What is the Nano Foudroyante EWT?
Greubel Forsey introduced the EWT for the brand’s twentieth anniversary, describing it as its tenth Fundamental Invention. The Fédération de la Haute Horlogerie (FHH) identifies it as a monopusher flyback chronograph with a perpetual foudroyante display and Greubel Forsey’s first flying tourbillon.
A foudroyante, or jumping-seconds, hand divides a second into visible fractions. On this watch, that display operates independently of the chronograph’s elapsed-time function. “Perpetual” here describes the display running continuously while the watch is operating; it does not mean a perpetual calendar.
How does the foudroyante mechanism work?
The balance oscillates at 3 Hz, or 21,600 vibrations per hour. The foudroyante hand makes six jumps per second, giving a readout in sixths of a second. As FHH puts it in its Nano Foudroyante EWT profile: “Each oscillation of the 3Hz (21,600 vibrations/hour) balance produces six beats per second.”
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- Seagull ST1901 Movement: Official exclusive 3A level ST1901 movement, ensuring precise timekeeping and reliability. Aviation Chronograph
- Retro Chronograph Design: Features a retro chronograph design, reminiscent of the 1963 Seagull pilot watch, with a functional stopwatch
- 30m Water Resistance: With a 30m water resistance, this watch is suitable for everyday wear and splashes of water
- Comfortable & Stylish: Comes with a durable leather strap, offering both comfort and a rugged aesthetic for everyday wear
- Durable Construction: Crafted with 316L stainless steel case, mineral glass crystal, and 30m water resistance, built to withstand daily wear
The hand is mounted on the flying tourbillon and stays vertically aligned as the tourbillon rotates. That arrangement lets the fractional-second indication remain legible while the assembly turns.
What “nano” means
The name refers to energy management on a nanojoule scale, not nanotechnology in the sense of parts manufactured at nanometre dimensions. SJX notes that the components are still large enough to handle with tweezers. It is more accurate to describe the watch as using energy-efficient micro-mechanics.
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- CLASSICAL 1963 CHRONOGRAPH:The watch is equipped with the original ST1901 chronograph manual winding movement,When the watch stores full energy,Can working 40-hours;Vibration frequency 21600VPH ,21 jewels stable bearings,reduce wear and improve the service life of the movement.Mechanical hand winding movement
- 3D ACRYLIC MIRROR MATERIAL：The watch uses Acrylic glass mirror,Unique mineral 3D domed mirror, light transmittance is 99.8%, 316L stainless steel case, vintage ivory dial, blue pointer and three-dimensional gold Arabic numeral scale, comfortable and breathable nylon strap, with buckle design, the strap length is adjusted according to the wrist size
- WATCH FEATURES: The diameter of the watch is 38mm, the thickness is 13.5mm, and the strap width is 18mm,Display back cover,Feel the beauty of mechanical motion;30m/3Bar/3AM daily life waterproof design, able to withstand light rain and splashing water, not suitable for bathing, swimming, and diving. Do not use the timer function in water.
- USE INTRODUCE：Start use the watch, please manually adjust the crown 30 to 40 turns first. When the crown cannot rotate, it indicates that the watch has stored full energy; Please stop adjusting the crown at this time, otherwise it may damage the movement spring.Sub dial chronograph second and 30 minute Sub Dail,can record every minute and second,Please Note:When watch stores energy, Sub-dial chronograph second hands can work continuously and cannot be controlled.
- PERFECT GIFT: This is a classic pilot timepiece with a rich historical and cultural heritage. The exquisite design perfectly blends with the functions of the timepiece, making it perfect for men's daily lives, dates, and meetings to wear; It is also the preferred gift for graduation ceremonies, birthdays, weddings, Father's Day, Christmas, Thanksgiving, Halloween, and Valentine's Day.
The energy figures
FHH reports Greubel Forsey’s figure of 16 nanojoules for each foudroyante jump, compared with 30 microjoules for a conventional foudroyante, and describes that as a reduction by a factor of 1,800. These are maker-reported figures presented by FHH; the sources available for this article do not establish independent laboratory verification.
Original EWT specifications
| Specification | Original Nano Foudroyante EWT |
|---|---|
| Movement and functions | Manual wind; monopusher flyback chronograph; flying tourbillon; foudroyante display (FHH) |
| Movement components and jewels | 428 components; 42 jewels (FHH) |
| Frequency | 21,600 vibrations per hour (3 Hz) (FHH) |
| Power reserve | 24 hours with the chronograph running (FHH) |
| Case | 37.90 mm diameter; 10.49 mm thick; white gold with tantalum (FHH) |
| Crystal and water resistance | Sapphire back; 30 m water resistance (FHH) |
| Edition | 11 pieces (Hodinkee, 2024) |
| Launch-era indicated price | CHF 465,000 (Hodinkee, 2024) |
The stated 24-hour reserve applies with the chronograph running; it should not be read as a published reserve figure for the chronograph stopped.
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- Gold Swan Neck Regulator
- Column Wheel Chronograph
- Luminous Hands
- Blue steel screws
- Exhibition Case Back Cover
Price, edition size and availability
The original EWT was presented as an 11-piece experimental edition. Hodinkee reported in November 2024 that all 11 had been allocated, alongside a launch-era indicated price of CHF 465,000. That is a historical allocation report, not confirmation of current resale availability or a present-day market price.
On fit, Hodinkee’s author observed that the watch sat relatively high on the wrist despite its 10.49 mm stated thickness, attributing the impression to the lug shape and domed crystal and caseback. That is one reviewer’s experience, not a universal fit assessment.
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- Man Watch: Sugess Upgrade Gold Swan Neck Sea-gull ST1901 movement keeps accurate time, provides 45h Power reserve, 21 jewels, 3Hz(21600BPH) in frequency. Mechanical watch hand winding, without battery. Men casual watch with gooseneck, a fine-tuning device, which can make the time more accurate and stable
- Multifunctional Design: Chronograph watch with Second and minute sub-dial support stopwatch. Wrist Watch with luminous hands can see the time in dark. Men classic watch with comfortable black leather strap, durable and comfortable. Diameter 40mm, thickness 13mm
- Waterproof and Anti-scratch: 5 ATM(50 meters) water resistance, suitable for daily activities, can bear sweat, accidental rain or swimming. Stainless Steel watch case with anti-scratch Sapphire dial, sophisticate crafted and durable
- Best Gift: Classic wristwatch is a perfect gift for for festival, family, and meetings. Man wristwatch are the first choice gift for graduation, birthday, wedding, Father’s Day, Thanksgiving Day and valentine’s Day. Chronograph analog watches are the ideal gifts for father, boyfriend or other male friends
- What you get: A Sugess Watch, an instruction book, a guarantee card, a adjustment tool and a cleaning cloth. Your satisfaction is our priority. If you have any questions about the casual men fashion watch, please feel free to contact us. We will give you professional service in 24 hours
How the 2025 collection version differs
Greubel Forsey presented a separate 22-piece Nano Foudroyante collection edition in August 2025. Time and Watches describes it as the transition from the experimental EWT series to an independent collection creation. It has an all-white-gold case, revised dial details and a blue rubber strap; the original 11-piece EWT instead pairs white gold with tantalum. The 22-piece edition is distinct from the EWT, so its materials and edition count should not be attributed to the original watch.
What to compare when evaluating one
For an EWT or a comparison with the later collection edition, check the exact edition and case material, the movement architecture, whether the foudroyante runs continuously, and the stated reserve with the chronograph engaged. Case dimensions, water resistance, dated availability and the price basis also matter. The figures above establish launch-era specifications and pricing, not a current value-for-money ranking or market-price comparison.
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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.
