IWC

… ref. 3700, still on the GEO1 bracelet. Porsche Design. Said to have been the first chronograph in titanium in the world. 

But these proprietary bracelet technologies…. I Was never able resolve this one i have two. One converted to lug holes the other still in the drawer. 

GEO1 (single-pin as seen in your upper picture) to GEO2 (double pin) to GEO3 (horizontal pins through the entire link). They had to consequently adjust the watch heads (which they usually did during a regular service). Most Titan Chronos and most Ocean2000 have over the many years been "updraded" to GEO3 which is why good examples with the original GEO (1 or 2) are more rare to find.
Cheers, HSTE

The bead blasted finish is superb too.

This watch started my passion for watches 35 years ago. At the beginning of my hobby it was unattainable for me. Today it is in my collection. 👍

Just wonderful, historical, practical, and above all very cool!!!

My Geo3 with adjustable Ti bracelet during date change. I always thought of the three (Refs. 3551 and 3524), this one was the least interesting. But like anything deep, I learned to enjoy its boldness and at the same time, details and fit and finish gradually. This is a very nice big watch with comfort to boot because of its adaptable Geo3 bracelet. 

I sold the first one to a friend who never wears it



The second stopped working and they told me "Don't send it, we can't / won't fix it"







Plus the strap is very dodgy now, as the rubber material is coming apart.