[wallcraft]

Originally Posted by WFT

I checked the MobileRead E-book formats wiki page and found four eReader-specific formats, as follows:

1. -ER.PDB
2. PDB
3. PNPd
4. PRC

Which one is preferred for eReader?

If you distribute an eReader file, it should be .pdb. Fictionwise uses "-er.pdb" as a convention to make clear that this is a eReader ebook because several ebook formats can have the extension .pdb. You can do this if you want, and it may reduce confusion, but it isn't necessary if you only have one .pdb type.