From the Manufacturer
Read and write secret messages, anywhere…in light or darkness. Includes invisible ink and a hidden UV light that you can position at any angle…all built inside. Ages 8+.
This Spy Net invisible ink pen is what you need to read and write secret messages. It has a LED light to read in the dark! Spy Net invisible ink pen Read and write secret messages Create secret messages no one else can read Built-in LED light allows you to read in the dark Requires 3 AG13 batteries Recommended for ages 6 and up Brand is Real Tech Spy Net