The special pen reveals the invisibly printed answers. See how much you know with hundreds of interesting questions on dozens of different topics. Have fun competing with the invisible opponent as you play games by yourself.
Check out all 6 books in the Yes & Know® Invisible Ink Book series.
• special pen
• 48 pages of fun games and trivia
Book Size: 6" x 11"
UPC: 0 77259 01121 7
Product Code: YK12