When exposed to oxygen, the iron in the pouch oxidizes and produces heat.
- When iron oxidizes, it produces iron oxide - more commonly known as rust.
- The salt acts as a catalyst, while the carbon helps disperse the heat.
- The vermiculite is used as an insulator for the purpose of retaining the heat.
- All of these ingredients are enclosed in a polypropylene bag.
- Polypropylene allows air to permeate the ingredients while holding in moisture.
