Age 3+. The special pen does it all! 2 in 1 activities. The special pen reveals the invisibly printed pictures and answers! Unscramble the stickers to create a surprise picture! www.leemagicpen.com. Facebook: www.facebook.com/magicpens. Conforms to ASTM D4236 - Non-toxic. From the makers of Yes & Know Game Books (Trademark of Stry-Lenkoff Co.). Marvelkids.com. Printed in USA.