I just received a 5600c (691) from uzj100. It had just received a bezel and strap change and looks incredible. The crystal is in great shape too. Just lovely.
This is THE official watch of underground mining. It seems everyone had one strapped on. That environment was more abusive to a watch than anything you can think of. Underground was the unofficial g-shock testing facility and testing went on 7 days a week for years on end.
This watch is my replacement for a 5600 that froze to death on Porcupine Lake.
Here's some quick pics. If anybody has some neat info on the 5600c 691 module g-shock, or any other older 5000s, 5300s etc, I look forward to your comments. I am rediscovering what a simple practical and tough watch this really is. It may be the most resilient watch in the world.