kn95 manufacturer in china: The most important feature of KN95 masks is that they can prevent droplet transmission caused by splashes of bodily fluids or blood from patients. The size of droplets is from 1 to 5 microns in diameter. 3M medical protective masks have the protective performance of medical surgical masks and particulate protection masks, which are used in hospitals to filter airborne particles and block droplets, blood, body fluids and secretions.