SUPPLYAID's KN95 5-ply Foldable Mask with Exhalation Valve is suitable for adults' daily travel protection. The KN95 mask is not to be used as a replacement for gas masks or as a medical mask. The mask cannot generate oxygen and should not be used in hypoxic environments. When used properly, the mask provides approximately 95% filter efficiency and effectively protects respiratory health. The one-way exhalation valve blocks particles upon inhale and releases air upon exhale. Use the KN95 mask to protect against PM2.5, dust, pollen, microorganisms, and air pollution. Use the mask within 3 years of manufacturer and should be stored in dry and ventilated location 23ºF - 122ºF (-5ºC - 50ºC, relative humidity 80%). Contains 5 face masks. How to wear: Please check for air tightness after wearing the mask. Check to ensure the mask is tightened securely to the face. Position the protective mask gently with both hands and be careful not to disturb the mask's seal across the face. To test for air tightness, exhale sharply through the nose. If you feel air leak from the nose piece, adjust the nose clip accordingly. If you feel air leak from the edges of the mask, re- position the ear bands. Color: White.