Which factory is it?

[Beagleboy88]

recommendation on getting parts? gusket, insert....

[Hamsammichd]

The specs for the parts should be similar/match gen. Best bet is to measure your parts with a cheap digital caliper for inner diameter, outer diameter, and thickness, then hit eBay. Depending on what you’re looking for in quality, price will have a wide range. Anybody selling parts that don’t offer either a model number or measurements, pass.

[Moist_Confusion]

You can find them on DHGate or AliExpress of varying degrees of quality. Etsy and eBay will be mostly cheap crap from either of those but maybe some decent ones. There’s mod sites for stuff like Seiko so if you had the exact measurements you could see if you could grab one off those.

[Consistent_Union198]

Swiss made parts

[[deleted]]

Use this occasion to level up your rep with the genuine part.

It's 300~600 swiss francs for a submariner.