From the Manufacturer:

Sapphire dial and hour circle in 18-karat white gold. 18-karat white gold case. Self-winding skeleton mechanical movement. Power reserve of 68 hours. Diameter 41 mm.

The Grande Seconde incarnates the essence of the Jaquet Droz watchmaking art. While the brand has oft varied its design, for the first time it proposes a sapphire dial integrated within a skeleton composition. The Grande Seconde Skelet-One marks a true stylistic turning point in the brand's history, as part of its prestigious 280th anniversary celebrations.
The objective of this creation was to let light shine to the deepest reaches of the Grande Seconde, all while preserving the figure '8' shape that is its aesthetic signature. To do so, Jaquet Droz maintained the uncluttered character of the dial that is distinguished by the legendary hours and minutes counter with Roman numerals at 12 o'clock, intertwined with the large seconds counter with Arabic numerals at 6 o'clock. The composition stays true in all aspects to the original inspiration of the Grande Seconde, playing with decorated surfaces as much as empty spaces. As in music, where rests count just as much (if not more) than notes, the Grande Seconde finds balance as it alternates between full and empty.
Similarly this new interpretation in total transparency - a first for Jaquet Droz - accords ample breathing space to the time indications. Hours, minutes and seconds stand out in a new transparent aesthetic bathed in light. Jaquet Droz has left only the bridges showing, which structure the piece's movement.
The sapphire dial, on which the large seconds hand turns, perfectly complements the skeleton movement, constructed in successive layers, themselves visible from the side. The plate is now entirely openworked. The casing-up circle has been eliminated, allowing for a more open composition. At 12 o'clock, the hours and minutes turn around a sapphire hour ring, set on a base of gold. The ensemble is held together by five indexed screws, oriented in a chosen direction. Used for the first time by Jaquet Droz, this procedure was derived from an existing armory system and adapted by the brand's technical teams. The oscillating weight in gold has also been openworked to let light diffuse freely into the heart of the movement. The Grande Seconde Skelet-One, equipped with a silicon double barrel, balance spring and pallet lugs, features a hand-assembled Caliber 2663 SQ. It is the first to reveal the mechanical choreography beating at the heart of the Grande Seconde.
The Grande Seconde Skelet-One, with a diameter of 41 mm, comes in three interpretations: red gold, white gold and ceramic.