The Big Pilot’s Watch Constant-Force Tourbillon Edition “Le Petit Prince”(ref. IW590303) is the first pilot's watch from IWC to feature a constant force tourbillon. It is available with a hard gold case and is limited to just 10 watches. This is the first time IWC has produced a watch with hard gold, a special new version of red gold. The microstructure of the alloy is modified in a sophisticated manufacturing process. Hard gold is therefore significantly harder and around 5 to 10 times more wear-resistant than conventional red gold. As a result, the material is perfectly suited to the large case and the crown of a Big Pilot’s Watch. The combination of the mesmerizing constant force tourbillon with the poetic design elements of this Le Petit Prince edition, make this timepiece exceptional. The red gold case creates a beautiful contrast to the blue dial and moon-phase complication.