Omega 198.0055 - Hard metal hummer

This is my first venture out of the Universal Geneve sub-forum so please bear with me; I'm interested in people's opinions on a watch that I bought a couple of years ago. One member here, Tom Dick, assisted me when I bought it and I've been meaning to write something since; I spend far more time on TZ-UK than is probably good for me and the acquisition coincided with an ongoing saga about a particular Omega prototype and this put me off at the time.

This is the watch:








In my enthusiasm I sent off to Omega for an Extract however this wasn't as helpful as I had hoped; my understanding is that the extract is for the watch that was pulled off the production line to provide the innards for this watch. The case reference and case metal is obviously nothing to do with this watch.




There is already one thread in existence and this was created by Paul from Electric Watches; Paul completed the service for me.
http://www.thewatchforum.co.uk/index.php?/topic/95561-omega-f300-hard-metal-mystery/
I also found this thread about a Tissot in the same case (interestingly a second example of the Tissot came up for sale on TZ-UK recently).
https://omegaforums.net/threads/uber-cool-tissot-omega-hard-metal-prototype.36722/#post-419864

In the interests of full disclosure the mesh bracelet is after-market however the clasp is from a Ploprof.

Tom Dick says it is and that's sort of good enough for me 😀. As far as I can see it's exactly the same case as the Tissot. It definitely does have a different lustre to stainless; sort of a smokey bluey-grey. It's very difficult to photograph.

Good question. The watch does appear to have a sapphire crystal which matches with the entry found in the Omega Dressings Catalogue for 198.0055; something I understand to be unusual for a f.300. I have no reason to believe that it's from a donor but I'm obviously interested in views here.

I also have a Tissot that just looks like your Omega:

https://uhrforum.de/rado-certina-eterna-aus-wolframkarbid-t157975#post3552600

The case material is tungsten carbide. In the past Omega and Tissot did a lot together, so it would not be unusual to find the same watch with Omega and Tissot logo.