Lightweight and breathable, ideal as a third layer for cloth face masks. This non-woven spun-bond Polypropylene is 1.25 ounce per square yard (on par with most surgical masks), and is best used in conjunction with tightly-woven cottons for good quality filtration. Machine Wash and Tumble Dry Low. Do NOT use a direct iron - material has a melting point of approximately 320*F. If you must iron your project, be sure to use a low heat setting and a pressing sheet or other heat barrier.