Fine if you don't overheat the water
These are great for the price. I bought them to use under my motorcycle helmet, we'll see how they hold up.<br /> The trick is to not overheat the water. It's easy to super heat water past the boiling point in a microwave. These will disintegrate if overheated. I think the water should be between 190-200 F, maybe even cooler. They are a little easier to handle if they aren't too goopy from being too warm.
Rating: 4 stars