A spy pen to keep their secrets safe from prying eyes! A spy needs to keep their secrets safe from prying eyes! Use the invisible ink pen to write them down in this awesome activity book. Learn code languages, take fingerprints, answer questions like "My best spy hiding place is ____", or take fun quizzes. The only way to read your secrets is by using the UV flashlight on the pen cap. Without it, the pages of your notebook will appear blank leaving all uninvited readers none the wiser. Your secrets are safe!