50PCS Disposable 3 layers protective Face Mask Why/When/where should I wear this mask? The new guidance of CDC highly encourages public to wear face masks in public settings like marts, streets, grocery stores as social adaptation. These masks have the following features: ?? 3-layers of Protection: Made with three layers of soft non-woven polypropylene that prevent the inhalation or exhalation of respiratory droplets. ?? Easy to Breathe Through: Highly breathable non-woven fabric makes breathing just as easy as if you weren?t wearing a mask. ?? Comfortable Fit: This mask is only 0.4 mm thick and adds almost no pressure to your face. The elastic ear loops are flat and designed to fit the ear without excessive strain. ?? Skin-Friendly Materials: Made of soft, non-woven fabric that is odorless and soft to the touch to avoid skin irritation.   ?? Fluid-resistant and provides the wearer protection against large droplets, splashes, or sprays of bodily or other hazardous fluids. Helps protect others from the wearer?s respiratory emissions.    ?? Loose fit ?? Store in a dry area at room temperature. ?? Free reliable shipping by USPS ?? Shipping only available within the US - no international shipping Is this mask one size fits all? One size fits all with the straps behind your ears. Can these be returned?  Kindly be advised that due to the nature of the mask, this item is NOT refundable and returned once you open the pack and use them. Why/When/where should I wear this mask? The new guidance of CDC highly encourages public to wear face masks in public settings like marts, streets, grocery stores as social adaptation. In this unprecedented pandemic, you should put on a mask whenever you are in a public place, or exposed to others.  Importantly, wearing a mask will prevent you from getting infected by someone outside and unknowingly spreading disease in public if you are infected but asymptomatic.