The team from MIT chose to use silicone rubber for the main part of the mask in part because of its durability—it’s the same material used in some baking equipment, and can easily withstand high temperatures. In a study of a prototype of the new mask, the researchers tested sterilizing it in an oven. They also tested a steam sterilization device and by using bleach or rubbing alcohol. Nothing damaged the material. Because it can be sterilized in several different ways, it can be used anywhere. Two breathing holes in the mask use small N95 filters that can be popped in and thrown out after each use. By using far less material, it should be possible to meet demand more quickly. It also reduces waste. But the researchers are also exploring the use of a different filter material that could be sterilized and reused.