Your mug is printed using the sublimation process - it has a special coating into which the design is incorporated under high temperature and pressure giving excellent reproduction with vibrancy, sharpness, and permanency. Because the design is incorporated into the surface your mug is completely smooth (unlike with traditional printing which merely prints onto the surface) and the design cannot be washed, scratched, or rubbed off unless the coating becomes damaged so your mug will keep looking good!