The Blancpain Villeret reference 6638-3631-55B features a 42mm case crafted from rose gold. This timepiece is powered by the automatic winding Blancpain caliber 3863, which was introduced in 2004. The watch displays a white dial and includes functions for date, month, leap year, perpetual calendar, moonphase, and equation of time. Its intricate design and functionality make it a notable addition to any collection.