Generally speaking, modern self-winding chronograph movements don’t give an impression of fineness, which is scarcely surprising when you consider that by and large, they are built for durability and dependability first, as they’re going to go into watches that are expected to be able to take a little rough-and-tumble wrist time. Practically speaking as well, it’s pretty difficult to slim down an automatic chronograph. They’re generally built on three levels: there’s the mainplate, which carries the basic timekeeping train; above that, there are the chronograph works; above that, there’s the automatic winding system. This is probably a major part of the reason that, while there is something of an arms race going on in extra-flat watchmaking, extra-flat chronograph design has been essentially static for many years. F. Piguet (now Manufacture Blancpain) came out with the caliber 1185 and its automatic counterpart, the 1186, in 1987 and at 25.6mm x 5.5mm, the 1186 has been the thinnest full-rotor chronograph movement ever since. (Vacheron at one time used their version of the 1186 in the Overseas line, as the Vacheron caliber 1137, but has discontinued its use).