The M5 was designed to be used on your phone or tablet (as well as your home computer), because that’s the way you live. Study a few questions on the bus, while waiting for your oil change, or in the OR. Wherever you go with your phone, the M5 goes with you. Carrying books with you from place to place is burdensome and unrealistic with the final result being numerous wasted opportunities for study. If you have an internet connection, you have the M5.