17AT

The 17AT, like the 17P and 17AP, derived from the ebauche by Le Phare. 

In the beginning, Le Phare produced these movts for Bulova and others, eventually making their name in the world of complicated repeater movements and chronographs by the end of the First World War.  Much later, they utilized other makers themselves, so you will find Landeron and Venus in Le Phare Chronographs of the 50's and 60's. There is not much information on these early ebauches.