Design Your Own Mugs. A great gift idea for teachers parents and friends our Design Your Own! mugs are fun and easy to decorate! Mugs pull apart and snap close easily to place insert. Each plastic mug includes a blank paper insert to color and decorate. 4 8 oz. Remove insert before washing. We recommend using crayons colored pencils permanent markers or tempera paint sold separately online. OTCAge RecommendationAges 5 & Up Containing medium-sized pieces with the occasional angular edge these lightweight to sturdy crafts may require some assembly such as stringing beads or gluing items to create a 3-dimensional project.