[BetterRed]

@DelennDax7 - first you can Merge the PDBs and EPUBs into one 'book', sort them on title and author, select a pair of lines in the Book List and press 'M'.

You could create a Virtual Library for the PDB's with this search term

formats:"=PDB"

Then you could use the Save to Disk feature within that virtual library to save all the PDB's to wherever.

But, why do you have to move the PDB's. I am not familiar with eReader Pro and I'm not sure I've ever seen a PDB - so the following is guesswork, and assumes you're using Windows.

Assuming you can associate the PDB file type with eReader Pro (double click a PDB in Windows Explorer, if it asks how to open, Browse to eReader Pro.exe and select it), then uncheck PDB in the Preferences->Behaviour->Use internal viewer list for: list.

Now, when you view the book from within calibre (press 'V') and select the PDB format the eReader Pro program should spring to life showing the current book.

BR