POOF-SLINKY-Secret Messages Kit. The Slinky Secret Messages kit is the fun way to learn about cryptology-the science of secret messages! Explore the methods behind codes, ciphers, hidden messages and more! With duplicates of all contents, this complete kit contains everything you need for you and a friend to send secret coded messages just like real spies! This kit contains two manuals, two tubes, four red caps, two markers, four crayons, one red plastic screen, two fasteners, eight cipher wheels, and two cipher cards. Recommended for ages 8 and up. WARNING: CHOKING HAZARD-Small Parts. Not for children under 3 years. Imported.