1mm. Although AP promoted the watch as “Additional-Thin,” enthusiasts continued to consult with it as “Jumbo” presented its 39mm scenario. Other slight modifications involved a swap from a white day wheel into a black Model to the blue and black dials as well as the addition of a double-deployant clasp https://www.watchesworld.com/a-guide-to-10-of-the-best-dress-watches/