This is a great brainteaser set for kids and adults. This can be used for both parents and kids to have fun in their free time. This can also be used for the kids as a stem or as a brainteaser puzzles for using their brains skills and other skills to do it. This is made of wood and metal with the smooth surface, non-toxic material is safe for kids. This can also be used as a party fun like a challenging game and can be used in different ways. There are total 10 puzzles, one ball one wood cross puzzle and eight metal puzzles.fun to do.