That’s a beautifully finished solid gold pocket watch, there isn’t much market for them so most are worth just a bit more than melt value but that’s one of the most intricately engraved Omega examples I’ve seen. Taking good photos and listing it in a no reserve auction somewhere would be your best bet unless you want to hold onto it for sentimental value but due to the fact that nobody wears pocket watches these days it won’t be much more than gold scrap value sadly.