SSKFIf you dig a bit through the discussion below, you'll see the answer. People have posted the process a few different times - complete with pictures. AAW will also send you clear, detailed instructions for doing this correctly after the drop finalizes, so there's nothing to be concerned about. General consensus is that the required impressions will probably cost $50-100 USD (depending on the prices charged by your local audiologist). Make sure to take AAW's instructions with you to get the impressions done so they're done correctly and so you're only being charged for what you need.
TL;DR: You get a local audiologist to create a very specific set ear impressions. Then you send a pic of the results into AAW for approval. Once your impressions are approved, you ship in the impressions for AAW to create your cIEMs.
blur510In theory you can and we have done it before, but we cannot guarantee the safety of it since the casting process is pretty dangerous. If your custom IEM is an old pair and you intend to discard it anyway, you may do it. It will be up to you. The usual case we see is, customer send in one pair of old CIEM for reshell and use its shape to build a new pair as well.
If I choose the CIEM, do I need to send ear impressions to you by myself? Or Massdrop will handle them.