The Franklin SDU-320 Sudoku Puzzle provides millions of Sudoku puzzles, the game that has swept the nation. Sudoku is a game similar to a crossword puzzle that uses numbers instead of letters. No math is required and the game is simple to learn; anyone can pick it up and start. This handheld device features a touch screen display and a stylus, for easy input. Millions of computer generated puzzles are included. Additionally, there are also handcrafted puzzles by experts that enrich the experience by creating interesting solution processes for the puzzle enthusiast. You can choose from three different skill levels, and the device also features a puzzle builder and solver. The Franklin SDU-320 Sudoku Puzzle requires two G13 batteries (included).