A PDF with a paper size of 4.13 x 5.85in (A6) suitable for viewing on mobile devices and smaller tablets.
An open e-book format compatible with almost all e-book readers, including the Nook and several apps for iOS and Android devices.
An e-book compatible with newer Amazon Kindle devices (running firmware version 4.1.0 or later).
An e-book compatible with all Amazon Kindle devices. If the AZW3 format does not work on your Kindle device, use this format instead.