Hot Air Cotton For Mask is used to stay comfortable, durable after each wash and can last for a very long time. It is ideal to protect mouth and face from dust, haze, allergies, smoke, pollution, ash, pollen, hazardous chemicals, heavy metal particles etc. Furthermore, this Hot Air Cotton For Mask will not cause earache even if worn it all day. It is washable and reusable. It can be washed repeatedly and durable without deforming.