Electronic Sudoku game stimulates the mind and logics which exist in each and every one of us. Studies show that playing Sudoku improves your memory, mind clarity, and even your IQ! Some scientists and researchers recommend playing Sudoku as part of regular daily activity. Playing levels LI-L5. This item contains small parts not suitable for children under 8. 2 3/4" x 3/4" x 4 1/2" high. Uses two AAA batteries (not included).