patrick_y[PuristSPro Moderator]
33543
Patek's 240 caliber is my favorite!
I fell in love with Patek Philippe back when I was a teenager because of the 240 caliber. It's sublime slimness and that micro rotor (admittedly my first time noticing a micro rotor) intrigued me and the high quality finishing finished me off.
I always considered the 240 caliber to be an Ultra-slim watch. And as far as automatics go, we're probably not wrong (although Piaget has some even slimmer automatics). But as for manual winds, definitely has to be below 2mm.
I really like the 240 caliber though; it's a great balance of practicality. Slim enough, probably more accurate than an Ultra-slim watch, a reasonable power reserve, and overall more practical.