Quoted from the following purchase site: ▼ [Carefully Finished] Made of non-toxic and harmless ABS material, the surface of the balance scale is smooth, so there is no need to worry about scratching children's hands. [How to Play] Observe the deflection of the balance scale's needle and adjust the weights on both trays to maintain balance. Traditional weights are replaced with candies and numbers of the same weight, making math enlightenment more intuitive and fun! [Improve Thinking Skills with Various Ways to Play] The balance scale toy comes not only with equally weighted candies and numbers, but also with math problem cards. From easy to difficult, children can gradually learn numbers, shapes, and addition/subtraction operations through play. This is a used item. Please consider purchasing only if you understand this. #EducationalToy #Math #BalanceScale #Weight