Secret Message Spy Pen, Decoder Wheel, Spy Ninja Notebook The Secret Message Spy Gear includes the Secret Message Spy Pen, Decoder Wheel, Spy Ninja Notebook, as well as some secret messages! The pen has a regular ink pen, an invisible ink marker, a secret message compartment, and a UV light for revealing the hidden message! Batteries required 3 x LR41 ( included) Changeable watch faces Product Description Hey Spy Ninjas! We are a team of best friends who create videos of our daily action-packed adventures. We use martial arts and detective skills to find clues and solve puzzles to defeat our enemy – evil hacker organization Project Zorgo, who intends on taking control of the internet!