My daughter got this craft as a birthday party favor. Both she and I loved this concept where kids could design their own mug. The mug itself has two parts - a white inner shell and clear plastic outer cover. Then there are 3 paper inserts with various pictures on them. Kids can color the insert and fit it easily between the shell and plastic cover. While the product comes with only 3 paper inserts, you can create your own. You can have more white papers with colorful pics, or you can have colored or sparkly paper inserts. The possibilities are endless!
The inserts do get soggy if you wash the mug as is. So a better way is to take out the inner shell and wash it separately. Also, the package says that the mug is good for both hot and cold beverages, but personally I don't trust hot beverages in plastic. In our house this is the designated 'Water Cup' for my daughter.
Overall, a great way to get kids to drink more water, especially during the summer.