5311 masks, products comply with GB2626-2006 KN95 standard, 4 layer filter, inner and outer layer of fabric: Cotton spunlace non-woven cloth, skin friendly electrostatic interlayer: KN95 meltblown filter, electrostatic filter cotton. Product features 1 by leading international electrostatic adsorption principle of non-woven fabric, fine particle diameter greater than 5 micron filtration rate greater than 95% 2 draping, built-in shaped nose, and face tight fit, after the start of the formation of three-dimensional space to breathe, breathe not oppressed. 3 high-tech ultrasonic point belt, strong, beautiful, long time wearing no ears pain.4. are warm, breathable, six color optional