Not sure if the 13mm is accurate, but I have one of their slim line autos with this same case and it's the slimmest wearing watch I have. The back is very soft and round and saucer like. The edges are quite thin. I have a large Swiss collection and the fc slim is by far the one which sits flattest on my wrist.
I actually find it looks odd at first since it's so flat compared my my sport watches.
JoeFlorida54It probably is 13mm cause it's using an in house movement. Their other slim watches are much slimmer but use the extremely slim 2892 sometimes with second hand removed to make it slimmer. An in house movement is an fairly prestigious feature in a Swiss watch.