The Kindle app for Android will open the .mobi files. I used Dropbox to get to the file and thought I’d just be able to open it from Dropbox into the Kindle app like I can on the iPad. That didn’t work and it told me to download an app that could open the file type. I copied it from Dropbox to my downloads folder then used a file manager to try and open it without luck. Then I noticed a Kindle folder. I copied the .mobi file into the Kindle folder then opened the Kindle app and it worked!