KINGOU Bamboo Green Octagon Lock Logic Puzzle Burr Puzzles Brain Teaser Intellectual Assembly Toy Green Six Sticks . Material: Bamboo. Size: 2.95 x 2.95 x 2.95 inch. Difficulty Rated:  . Recommended for ages 12 & up, water-based paint, touch smooth. When assembling requires careful observation and thinking, analyze its internal structure.Our mind puzzle help to exercise brain, develop intelligence, improve problem-solving ability, and also relieve pressure. As it is made by bamboo, the puzzle is a little tight and hard to take apart, so it is not fit for kids under 12 years. To make it challenging and fun, parcel without paper instructions, if you need solutions, please contact us.