H. Moser & Cie caliber HMC 803

HMC 803 description

HMC 803 calibre is entirely skeletonised. The bidirectional rotor, made from 22-carat solid red gold, is also open-worked. Fascinating and hypnotic, its oscillations set off the various materials and surfaces. Playing with surprising contrasts, H. Moser & Cie. uses this setting to showcase a most traditional and exceptional watchmaking complication, the tourbillon, giving it a contemporary twist with both lightness and subtlety. The Manufacture opted for a movement in nickel silver (or German silver, which is a brass alloy enriched with nickel), a choice dictated by history. The entire surface of the HMC 803 calibre is carved with a decoration that took almost 100 hours of work, and which further reinforces the unique nature of this exceptional watch. Finally, the Manufacture is equipping its masterpiece with a second time zone, indicated by a rhodium-plated hand, which can be easily distinguished from the blued steel hour and minute hands, and, of course, an Moser interchangeable minute tourbillon, boasting an original Straumann Double Hairspring®. This stroke of genius for a watch is intended to make watchmaking history and transcends the advantages of a simple tourbillon.


Movement: in-house automatic calibre HMC 802,
diameter: 34.0 mm, height: 6.5 mm
Frequency: 21,600 vib/h
Second time-zone display
Hours and minutes
Interchangeable Moser minute tourbillon
Moser teeth for all wheels and pinions
Original Straumann Double Hairspring®
Movement and components handfinished and decorated
Oscillating weight made from 18-carat red gold
Automatic pawl-winding system