Made of PP, silicone and mental, which is safe, non-toxic, durable, flexible, tear-resistant, not easy to damage, reusable. You can hold with one finger either side of the center and then with your other hand turn. Press the around bubbles they make a slight sound,endlessly repeat, find the fun. Can play anytime, anywhere, at the office, commuting, in class, studying, in meeting or watching TV. suitable for those lack of attention/with hyperactivity disorder, students, office workers, daily fun.