The sunray pattern engraved on the back of the pink gold case radiates
from a circular window whose diameter corresponds to that
of the three-armed carriage of the tourbillon regulator, a
subtle and complex mechanism enhancing the rate regularity
of the 19-jewel rhodium-plated movement,
measuring about 47 mm across and built for observatory competitions.
Also in pink gold, the dial carries applied Roman numerals
in gold, like the hours, minutes and seconds hands.