One and a half Gregorian years after launching the Tonda Hijri Perpetual Calendar, Parmigiani Fleurier revisits its groundbreaking world premiere in a limited series of three gem-set models. The new models come in cases set either with diamonds, rubies or emeralds, with the exact shade of rubies and emeralds selected specifically to pay tribute to the national colors of the countries in the Middle East region. Green is a shade with particular significance in the Islamic world, while red and white are present in almost every national flag across the region. Each gem-set variation of the Tonda Hijri Perpetual Calendar is limited to 10 pieces only, a true horological exclusivity.