A grand sonnerie is a very complicated watch complication that strikes on the hours and quarter hours automatically and can, upon demand, repeat the chimes. It is one of the most complex and challenging watch mechanisms, mostly used in high-end, more complicated timepieces. In addition to displaying hours, a great sonnerie displays time in quarter-hours- a true mechanical engineering marvel audible. The watches are excellent pieces and acquire more value as collectibles as collectors appreciate the art of traditional watchmaking and precision.