Armin Strom Gravity Equal Force Only Watch 2023

For the Only Watch 2023 charity auction, Armin Strom has created a unique edition of its successful Gravity Equal Force watch.

Introduced in 2019 by the Biel/Bienne-based independent luxury watchmaker, Gravity Equal Force is the world’s first automatic watch with a constant force transmission.

Founded in 2005, Only Watch has raised nearly CHF 100 million to accelerate the research on Duchenne muscular dystrophy. Created for the 10th edition of this event, the new unique iteration of the Gravity Equal Force ‘Ultimate Sapphire’ incorporates the promotional colors of the 2023 Only Watch event. It comes with a transparent green sapphire dial, a red logo and blue stitching on the included custom strap.

This timepiece offers an extraordinary view of the exquisitely finished manufacture movement, which features superior chronometric performance and exceptional hand-finishing, with a contemporary expression made in-house by Armin Strom’s master artisans.

Together with surrounding colourful details, the off-centre sapphire dial forms a deconstructed rainbow, which shares the dial-face attention with Armin Strom’s signature tri-bridge design.

This holds the microrotor, the winding mechanism and the patent pending Equal Force Barrel, an example of Armin Strom’s relentless quest to improve timekeeping. This innovation provides consistent power from the mainspring to the balance wheel, thus always ensuring flawless and constant precision during the power reserve.

The Gravity Equal Force Only Watch 2023 features an open-worked dial revealing mechanical dreams where all parts – even the invisible ones – are decorated by hand by Armin Strom’s in-house master artisans.

They demonstrate an extreme devotion to traditional haute horlogerie watch decorations, including polished bevels, black polishing, polished sinks, perlage and various grainings.

This is combined with a contemporary architectural design approach, which is clear in the signature tri-bridge, coated with dark grey ruthenium. These bridges are fixed with mirror-polished screws on the black movement plate, which is hand-guillochéd by Kari Voutilainen’s atelier.

The Gravity Equal Force movement, completely developed and manufactured in-house by Armin Strom, is the world’s first automatic watch movement with a constant force transmission.

The invention by Mr Greisler and his team is a unique stop declutch mechanism, which combines a Maltese cross, a technical solution normally found in hand-wound pocket watches, with an automatic winding system.

A Maltese cross inside the barrel controls the mainspring and stops it from fully unwinding. Armin Strom’s Maltese cross is, however, also declutched when the rotor has given the mainspring its optimum tension – a world first.

By cutting the top and the bottom parts of the power reserve, a constant force is delivered with an extremely secure, stable and precise amplitude and isochronism throughout the entire cycle.

Earlier, the brand created the Gravity Equal Force Only Watch 2021 unique piece for the ninth edition of the bi-annual charity event.

Technical details

Model: Armin Strom Gravity Equal Force Only Watch 2023
Ref. AS/ID ST23-GEF.SA.M.TX.N4

Indications
Hours, minutes, seconds, power reserve indicator

Movement
Armin Strom manufacture Caliber ASB19 Automatic winding with microrotor
Geneva drive Equal Force barrel, offset display with subdial seconds
Regulating system: Balance wheel with four regulating screws
Power reserve: Geneva stop-work limited to 72 hours
Dimensions: 35.52 mm × 11.67 mm
Frequency: 3.5 Hz (25,200 vph)
Finishing: Hand-finishing of the highest quality level
Jewels: 28
Number of components: 202

Case
Stainless steel case
Sapphire crystal and case back with antireflective treatment
Diameter: 41 mm
Height: 12.65 mm
Water resistance: 3 ATM

Dial
Green-toned, off-centre sapphire dial with subdial
Steel hands with hand-finishing and Super-LumiNova® filling, Manufactured by Armin Strom

Strap
Delivered with a black fabric strap with blue stitching and stainless-steel double folding clasp

Estimate
CHF 25,000 – 35,000
USD 27,500 – 38,500
EUR 25,800 – 36,100