Y&Y Star Kongming Three side open Magic Wooden Box with Extra Secure Secret Drawer, Brown YYaaloa Kongming Three side open Magic Wooden Box with Extra Secure Secret Drawer, Brown Box size: approx. 15.5cm*8.7cm* 5.4cm/6.1'' x3.4''x2.1'' It can only be opened if you know the trick otherwise nearly impossible to figure out the secret. inside for you to keep stuff safe. As a kind of Chinese traditional puzzle game, Luban lock carries with mysterious mathematical and physical principles. Foster logic thinking, relief stress, develop intelligence, train hand-eye co-ordination skills. Improve dexterity, tool for parent-child interaction, prevent Alzheimer's and more... All particles and shapes are even symmetrical, and logarithmic concepts are more helpful.