Favre Leuba Bivouac Ref 53203.
I have a huge fascination for vintage Favre Leuba, and especially the Bathy Fifty, a smart mechanical depth gauge in a wrist watch, and... The Bivouac, which is an altimeter AND a barometer, both mechanical.
I already posted the Bathy Fifty, let's now see the Bivouac.
Here is one in a blue dialed version. The silver dial exists, too.
Credit picture: Antiquorum.
In my wish list.