OTB to FB2 Converter
Convert your otb files to fb2 online & free
How to convert OTB to FB2
Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.
Choose "to fb2"
Choose fb2 or any other format you need as a result (more than 200 formats supported)
Download your fb2
Let the file convert and you can download your fb2 file right afterwards