The demand for masks during the epidemic is high, the quality varies, you can identify poor quality, “three no” masks by the following methods: 1, when buying masks, first look at the packaging. The package should clearly state the properties of the mask (single-use medical masks, medical surgical masks and medical protective masks). At the same time to see whether the package is marked on the production license number, the number will be with a “mechanical” word; 2, whether the package has the words YY0469-2011, but also in the State Drug Administration official website of “medical devices” page, enter the company to query. Page, enter the name of the enterprise to query, to obtain the production information and approval number of the corresponding enterprise; 3, the trademark is a brand identity, but also a guarantee of quality, to recognize the trademark to buy.