Oh, what a wonderful project this is. These little bags are easily constructed and then filled with regular rice. Heated in the microwave for just a minute or two then placed where needed to provide comfort. Use as you would a regular heating pad but without the hassle of a cord. And the longer ones can be wrapped around a knee or ankle and give warmth to the entire joint. A couple of these are backed in cozy flannel to provide a soft fabric next to your skin. Plus, if you keep one in the freezer you can also use it as an ice pack. How cool is that?!