If it’s plastic I’ve always sent 2 iges files of the inner and outer but written out in the assembled position so that the manufacturer can open them both to see how they’re supposed to fit. The link you have looks like all the vessels are glass? Best ring the manufacturer to see what they prefer, they might want other file formats etc.
We did a similar project and sent it to our client in China as separate parts in one assembly. We also sent SLAs to make sure that all was clear and that the transitions were understood…but ours had other parts too so perhaps that is not needed here.