iOS Apps (iPad, iPod touch and iPhone)
Each of these apps contain twelve books. Every book is professionally written for a specific reading level. The reading level is indicated by the yellow letter on the app icon.
These apps provide a password protected custom audio recording feature so that you can record any/all words in the correct pronunciation and accent for your region. Custom audio can be transferred between the apps, including to the macOS versions of these apps.
Did you know that a number of these apps are also available for macOS?