PRODUCT MATERIAL:Face: 100% polyester; back: 100% cottonPACKAGING MATERIAL:OPPHOW TO USE:1. Stretch the mouth mask to cover your mouth and nose. 2. Adjust the length of ear loops and put them around your ears. 3. Adjust the mouth mask for a comfortable wear.FEATURES: Soft and comfortable.PRECAUTIONS:1. Discontinue use if the mask has been contaminated or the breathing resistance is increased; 2. Do not use the product under situations of severe exercise or rapid breathing, to avoid adverse effects such as lack of oxygen.STORAGE METHOD:?