Learn how combination locks work and even build your own with this Combination Lock Kit from 4M. This set contains a plastic lock mechanism, a screw, a metal shackle, a sticker, and instructions. Choose your own secret code to ensure that only you can unlock your treasures. It also makes a great coin bank and secret message holder. Made of safe and high-quality materials, this Kit will last for years. This item is recommended for ages 5 and up.