As a detective, you need the right equipment for your investigations, including tools for writing and uncovering secret messages.
Exchange confidential messages with your fellow agent using disappearing and reappearing ink that only the two of you can read! Using either of the two secret pens, you can write a message that, once dry, becomes invisible. The other pen will not only reveal the information, but you can also use it to send your reply.
Use the special invisible ink pens to write top secret messages
One pen writes in invisible ink, second pen makes the writing visible
Includes tips and tricks for writing other secret communications