Eco-friendly material - The puzzle toy is made of high quality stainless steel with double layer plating, high toughness and no deformation, non-toxic. The material is not easy to rust, not easy to fade, sturdy and durable, The excellent processing makes the toy has smooth surface and not easy to hurt the hands. A good choice to train your brain or send as a gift. Classic games - This is a Chinese classical educational toy with have a long history and are enduring, it contain many mathematical and physical principles. While providing us with Entertainment, It can not only to release heavy stress but also helps to exercise your brain and practicing your concentration. Educational toys - includes 18 unlock toys, the simple design looks insignificant but actually its solution is quite complex. And which can enhance kids' Patience and thinking ability, good for creative thinking and developing intelligence, improve problem solving abilities while improve both your IQand eq. Offer you freshness and fun at any leisure time. For kids and adults - This is definitely a fun brain teaser toy that would be great for develop and promote children's logical thinking ability and practical ability, enhance the intelligence of the kids. While release the working pressure of the adults. Exercising elderly People brain, help prevent a decline in memory of the elderly. Suitable for everyone over 6 years old.