POOF-SLINKY-Secret Codes Kit. Send and Receive Secret Messages! The Slinky Secret Codes Kit is the fun way to learn about 'cryptology'- the science of secret messages! Explore methods behind codes, ciphers, hidden messages and more. Plus this kit contains duplicates if each item so you and a friend can share secret coded messages just like spies! This package contains two activity cards, two instruction manuals, eight code wheels (2 each of 4 wheels), two fasteners, and two markers. Recommended for ages 8 and up. WARNING: CHOKING HAZARD-Small Parts. Not for children under 3 years. Imported.