models which are animated by Piaget manufacture movements, the Black Tie collection presents models in round, rectangular, and tonneau cases, crafted exclusively in the various colors of 18K gold. The Black Tie watches range in scope from ultrathin manually wound models that feature the time only, to others which showcase power reserve and retrograde seconds. The ultimate expression of Piaget's watchmaking brilliance comes in the form of the Emperador Tourbillon watches, which presents a spectacular flying tourbillon whose elegant mechanics can be readily observed. Many models within the Piaget Black Tie watch collection are embellished with diamonds, which are painstakingly matched for color and clarity and set by the master jewelers of the House.