N95s respirators regulated under product code MSH are class II medical devices exempt from 510(k) premarket notification, unless:
The respirator is intended to prevent specific diseases or infections, or
The respirator is labeled or otherwise represented as filtering surgical smoke or plumes, filtering specific amounts of viruses or bacteria, reducing the amount of and/or killing viruses, bacteria, or fungi, or affecting allergenicity, or
The respirator contains coating technologies unrelated to filtration (e.g., to reduce and or kill microorganisms).
The FDA has a Memorandum of Understanding (MOU) with CDC NIOSH which outlines the framework for coordination and collaboration between the FDA and NIOSH for regulation of this subset of N95 respirators.
For additional differences between surgical masks and N95 respirators, please see CDC’s infographic.
https://www.fda.gov/medical-devices...-respirators-surgical-masks-and-face-masks#s3