Become an undercover agent and write a secret message with this special spy gear pen. The message is invisible for everyone, except the spy equipped with the developer marker. The Secret Marker Kit Spy Toy by Alex Toys is one of the bestselling spy gear kits for children's imaginative play. This secret message spy kit includes a broad tip secret marker, developer marker and 100-sheet notepad. Play secret messages with your siblings or friends, and fell like a special spy agent writing invisible notes. Secret Marker Kit Spy Toy from Educational Toys Planet makes a great small gift or unique party favor for your next kids birthday party.