Audemars Piguet produced very few chronographs in the early 20th century only 307 by their link count and this is one of the more interesting of the bunch. You might even remember the watch It made an appearance in Talking Watches with Alfredo Paramico back in 2014 and sold link at Phillips a year later too. That's where Audemars Piguet acquired it though the idea for this project started even before link the watch made its way into their collection. link