Fiberglass cloth.Fire blanket can extinguishes fire by suffocating it,so it extinguishes both liquid and grease fire. Emergency survival fire blanket ideal for the kitchen, fireplace, grill, car, camping and so on. Stops stove-top fires fast and is easy to use, safe, clean.The fire blankets is a great add on to your home fire extinguisher. Can also be used to wrap around your body and act as a heat shield.