Arnold & Son has created a patented constant-force tourbillon which is powered by the two mainsprings visible at the top of the dial.
A constant force device is used to equalize the amplitude — and therefore the chronometry — of the watch regardless of how much power reserve is remaining in the mainspring barrel(s). Like a constant force device, a tourbillon aims to improve chronometry (timekeeping/accuracy), although it does is by compensating in gravity, as opposed to controlling the power delivery. As the mainsprings unwind and smoothly deliver power to the tourbillon regulating mechanism, this in turn powers the hours, minutes, and most notably the deadbeat seconds hand (located in between 6 and 9 o’clock). For reference, a deadbeat seconds hand is an additional complication that makes the seconds hand tick like a quartz seconds hand versus the smooth sweep that is common in virtually all mechanical watches.
The hand-wound 3Hz movement (caliber A&S5119), features 39 jewels and has a 90-hour power reserve. Its components are made of nickel-silver and steel, with palladium treated bridges and an NAC treated mainplate. Bridges are hand chamfered with polished edges and brushed surfaces. Additional touches include screwed gold chitin and screws with beveled and mirror-polished heads. The tourbillon cage is mirror polished with hand chamfered polished edges and circular satin-finished surfaces.
A 46 mm diameter red gold case with cambered sapphire crystal and see-through caseback houses this superbly decorated and technically unique movement, while allowing views of the components at work from both sides. The water resistance is rated to 30 meters and the watch comes with a hand-stitched brown alligator leather with patina. Limited to 28 pieces. (Ref. 1FCAR.B01A.C112C)
This is a ridiculously technical movement, as we’ve come to expect from Arnold & Son. The constant force, the tourbillon, and the deadbeat seconds make for a very nice combination.