Brand Guides / Armin Strom / Mirrored Force Resonance
Reviewed by the Fine Watch Guide team · October 2026
The Mirrored Force Resonance debuted in 2016 with two regulating systems joined by a resonance clutch spring, and its 2022 redesign moved to the ARF21 movement.
The Mirrored Force Resonance is Armin Strom's manual-wind watch with two regulating systems. Its two balances are linked by a patented resonance clutch spring, and two seconds displays make the relationship visible on the dial. The model debuted in 2016 with the ARF15 movement, and the 2022 redesign uses the ARF21. The two generations differ, so the reference you own determines which service and parts route applies. Ask about the generation and the caliber before you commit to any work.
The Mirrored Force Resonance has two regulating systems, each with its own energy source and gear train. The brand's defining component is the resonance clutch spring, which couples the two oscillators so they can settle into a synchronized, opposing rhythm. This is a functional connection rather than a display of two balances for effect, and the brand's claim is greater rate stability as the oscillators influence one another.
The two seconds displays are the visible proof of that relationship. A pusher at two o'clock resets both seconds indicators, so the wearer can watch whether they continue running together. The pusher resets the displays and does not switch the resonance on or off, which is worth remembering if you expect a button that changes how the watch behaves.
For the owner, this design means the regulating system is part of the watch's character. A service that treats the two balances as separate jobs misses the point, and the coupling spring should be checked as part of the system.
The original Mirrored Force Resonance debuted in 2016 with the ARF15 movement, and the brand's owner's guide for that generation describes its manual-wind layout. The 2022 redesign introduced the ARF21, and it adds openworked balance bridges, slimmer lugs and a reduced lip at six o'clock, which makes the mechanism more visible.
A 2022 First Edition in stainless steel uses the ARF21 with a manual winding system, a 3.5 Hz beat, 39 jewels and 276 components, in a case 43 mm across and 11.55 mm thick. The power reserve is 48 hours, so a watch that sits unwound will need attention before it runs as it should. Check the reference against the generation, because parts and the appropriate service route can differ between ARF15 and ARF21.
Ask a shop which generation it sees most often and whether it has parts for both. A specialist who can tell you that quickly is more likely to plan the work well.
Armin Strom's owner's guides recommend maintenance every three to five years, carried out by the brand or an authorized retailer. Warranty work should go to an authorized center, since unauthorized work can invalidate a claim. Contact the Biel concierge before you send the watch, and ask for the estimate and the expected timing in writing.
A dual-regulator service should check both balances, both hairsprings and the coupling spring as one system. After reassembly, ask the watchmaker how the synchronized running is checked, and whether the result will be recorded. Ask for the seals to be replaced and for a water-resistance test if the reference is rated for it, since the owner's guides suggest testing every two years and whenever the case is opened.
For a watch out of warranty, an independent with experience of dual-regulator or resonance movements is the right type of shop. Ask how it handles the coupling spring, whether it has parts for the generation you own, and how it will show you the seconds displays running together after the work.
Start with the reference and the generation. The 2016 and 2022 versions differ in movement, bridges and finish, so a listing that mixes them should be questioned. Check the box, warranty card and service documents against the reference and serial number. Limited editions are common in this line, so confirm the edition number and the paperwork that comes with it.
Test the mechanism. Both seconds displays should run, and the reset pusher should return both to zero together. The watch should keep its displays in step once running, and the coupling should look clean through the openworked bridges. If one seconds display runs noticeably differently from the other, ask the seller to explain it before you pay.
Ask whether the case has been opened by anyone other than the brand or an authorized center, and ask for a service record. A written independent report that covers the movement, both regulating systems and the case is the strongest protection before you buy.
A specialist for this model should be able to name the generation, explain the coupling spring and say how they will check the synchronized running after work. Ask whether the shop has serviced another dual-regulator or resonance movement, and whether it will show you the result on the bench.
Parts can be the limiting factor. Ask whether the shop can source parts for the reference, what the lead time is, and what alternatives exist if a component is no longer available. A quote that leaves parts open is not complete, and it should say what will be replaced and why.
For the owner, the best outcome is a watch that runs with both seconds displays in step and that comes back with a clear record of what was done. Ask for that record and keep it with the watch.
It debuted in 2016 with the ARF15 movement. The 2022 redesign introduced the ARF21, which adds openworked balance bridges and slimmer lugs.
It links the two regulating systems so their balances can settle into a synchronized rhythm. The brand's claim is greater rate stability, not absolute accuracy.
The 2022 First Edition has a 48-hour reserve and is manually wound, so it needs regular winding to keep running.
Check the reference and generation against the papers, test that both seconds displays run and reset together, and have an independent examine the movement before you buy.
No. The pusher at two o'clock resets both seconds displays so you can watch them run together. It does not switch the regulating systems on or off.
Mirrored Force Resonance owners use Armin Strom specialists for servicing, authentication and restoration.
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