These 3D Maze Balls Are Designed with Different Difficulty Levels to Choose From, Suitable for People of Different Ages. They Can Help Students & Office Workers Relieve Stress From Study & Work, or Play with the Whole Family, Create a Warm & Romantic Atmosphere. These Brain Puzzles for Adults & Teens Need to Observe the Path of Game & Think About How to Get the Mini Steel Ball to the End. They Not Only Help Develop Spatial Cognition & Logical Thinking, Improve Concentration & Patience, But Also Relieve Stress & Relax Your Mind. Maze Puzzle Game Set Can Provide Hours of Fun for Most People & is Great as an Exquisite Gift for Your Family, Friend & Others Who Need to Reduce Stress & Exercise Their Minds on Birthdays, Christmas, Halloween & Family Gatherings. Minimum Quantity: 400.