D-ROAD Ultra-smooth Gear 3D Magic Cube 3x3x3 Cube Puzzle,Black Tension adjustable 3D gear is designed Art beats nature. Cube designer, 26 blocks of the cube is a gear, meshing Unlike ordinary 333 cube, with four water chestnut as the center fixing the whole cube Difficulty level:medium.Great choice for both beginners and cube game fans This product contains small parts, children below 8 years old needtheir parents to play with them, so as to avoid suffocation