Armin Strom Gravity Equal Force Ultimate Sapphire Blue: transparency and constant force

Armin Strom has presented Armin Strom Gravity Equal Force Ultimate Sapphire in steel with a blue guilloché main plate. Price CHF 27,500

Just a few days after the release of a rose gold version (read about it here), Armin Strom has presented a new interpretation of its Gravity Equal Force model with a cooler, glacial-toned aesthetic that highlights the transparency and depth of its unique architecture.

Housed in a 41 mm × 12.65 mm stainless steel case, the Gravity Equal Force Ultimate Sapphire Blue is reimagined through a refined palette of silvery greys and soft blue tones.

At its centre lies a richly textured, glacial blue guilloché main plate crafted by independent watchmaker Kari Voutilainen. 

Positioned asymmetrically on the left side, the open dial is made of transparent sapphire, revealing the silvery components below.

The cooler colour palette continues throughout the movement, with the micro-rotor, equal-force barrel and finger bridges hand-finished in rhodium to match the gear train and contrast with the transparent sapphire dial.

The watch is powered by Armin Strom’s proprietary Calibre ASB19, featuring a compact yet efficient micro-rotor, which makes it possible to preserve a thin and elegant profile.

This automatic movement features a stop-work declutch mechanism combined with a Geneva cross within the barrel, a patented system ensuring that the force delivered to the balance remains constant throughout the 72-hour power reserve, thus improving isochronism.

This solution pursues the same goals as complications like the fusée-and-chain transmission or the constant-force escapement, albeit in a different way. You can read more about how it works in our hands-on review of the Gravity Equal Force.

Visible through the front and back sapphire crystals, the 3.5 Hz (25,200 vibrations per hour) ASB19 manufacture calibre is beautifully hand-finished in all its components.

The bridges are bevelled and polished by hand, and the screws are black-polished. Decorative techniques like perlage, Geneva stripes and circular graining are applied with care, reflecting the brand’s commitment to traditional craftsmanship.

As with every Armin Strom creation, the watch undergoes a dual assembly process to ensure optimal performance and flawless finishing.

The Armin Strom Gravity Equal Force Ultimate Sapphire Blue is produced in a limited annual series of 25 pieces and is priced at CHF 27,500. arminstrom.com