Understanding FDA Certificates of Registration
First thing to do is look at a manufacturer's FDA Certificate of Registration. There will always be an acting agent that issues the certificate on behalf of the FDA. Some certificates differ from one another, depending on the agent. Ensure that it appears scanned, as stamps and signature markings are not digital and should be authentic.
Next, look up the manufacturer on the FDA Establishment Registration & Device Listing database.
Second, look at the Product Classification Code both on the FDA Certificate of Registration and also the FDA database. In this case, the product code is QKR and defined by FDA as follows. Understand the differences between Product Classification codes such as "LYU", "KHA", and "MSH" for surgical mask apparel.