This KN95 Nanometer mask serves as a disposable filtering face piece that provide respiratory protection. Protect your airways from dust particles, droplets, air pollutants, allergens, and other harmful air particles. Nanometer is one billionth of a meter. It serves to effectively filter 95 percent of airborne particles from the wearer to size PM2.5. To properly and effectively use the mask, place the mask on the face to cover nose to chin, and make sure to adjust the nose metallic piece to the shape of your nose. Effective filtration performance like N95.