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Armin Strom Clearly Resonates

Armin Strom really wants the world to have a clear view of its innovative Caliber 17 ARF, the oval-shaped mechanism powering its Dual Time Resonance wristwatch. By wrapping the dual-timer in a clear sapphire case, Armin Strom now allows an unrestricted look into all the specialized components that made the watch one of last year’s most interesting technical debuts.

Set in a broad 59mm x 43.4mm oval case, the Dual Time Resonance Sapphire offers a clear look into two independent movements in resonance. The keystone to the whole operation is the Armin Strom Resonance Clutch Spring, a tuning-fork-shaped metallic spring first seen in the 2016 Armin Strom Mirrored Force Resonance. Set between the two oscillators at the top of the dial, the Clutch Spring synchronizes the two movements as they keep time for the two blue guilloche dials placed horizontally across the case.

Resonance, a technically difficult and hard to regulate technique used by only a few other watchmakers, essentially means the two movements become synchronized as they operate. This creates a highly stable timekeeping rate that heightens the watch’s overall precision. When two movements resonate, overall operating efficiency improves while the potential of shock-inflicted error diminishes.

Indeed, Armin Strom say that its own laboratory testing has revealed gains in precision of 15-20% for two COSC chronometer-level regulated movements placed in resonance.

By spreading apart the two independent movements on the dial (and not stacking them vertically as they were in the Mirror Force Resonance) Armin Strom allows the wearer to utilize either dial to indicate GMT, a second time zone or to use as a timer. As with earlier iterations of the watch, the sapphire-cased model retains power reserve indicators on each of the dials and a 24-hour indication at 6 o’clock.

Armin Strom says that its Resonant Clutch Spring can take up to ten minutes to synchronize the two movements. To further back its claims regarding the technology, the CSEM (Centre Suisse d'Electronique et de Microtechnique) has officially certified Armin Strom’s resonance system based on the clutch spring as being a true system in resonance.

Clear case

Armin Strom says its desire to utilize sapphire to showcase the unusual ARF17 movement should be quite – ahem – clear. Armin Strom founder Serge Michel explains that “there is a lot of work done by hand and we wanted to have the possibility to show the 360° decoration on every piece from Armin Strom and this one in particular.”

He adds that his team found it difficult, however, to cut, mill, polish and assemble the sapphire crystal case components, especially given the large, 59mm long case. The team required diamond-coated tools to cut and mill the case components from blocks of sapphire crystal. After machining, the sapphire needs to sit untouched to allow any tension generated by the heat of machining to be evenly distributed. The case is then polished for days to make it transparent.

The Armin Strom Dual Time Resonance Sapphire offers the fourth case option for this eight-piece limited edition watch, with limited editions also made cased in titanium, rose gold and white gold.

Price: $268,000.

Specifications: Armin Strom Dual Time Resonance Sapphire


Movement: Armin Strom manufacture caliber ARF17, manual-winding, patented resonance clutch spring, dual off center time indications, 4 mainspring barrels, 3.5 Hz (25,200 vph), decorated base plate and bridges, 419 components and 70 jewels

Regulating system: Two independent regulation systems connected by a resonance clutch spring

Power reserves: Conical x 2, 110 hours for each movement

Case: 59 mm x 43.4 mm x 13mm sapphire crystal, front and case back with antireflective treatment, water resistant to 50 meters

Dials: Light and dark blue, hand guilloche, polished stainless steel hands

Strap: Delivered with a blue alligator strap and stainless steel double-folding clasp

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