Quality and use: 3Ply Disposable Mask, Kn90, GB2626-2006 (China National Standard); It is used for child protection. Generally, the cumulative time is 4-6 hours, 1 day or 2 days; Note:It is suitable for influenza, dust and droplet protection; it is suitable for densely populated places and it is more helpful for people to fight against the corona virus; It is not recommended to wear it for a long time during sports;Please pay attention to safe use. This sale belongs to protective materials, with small profit,we hope to overcome difficulties together.