Introduction of KN95 masks The KN95 reusable cloth mask is a reusable cloth mask that protects people from the SARS-CoV virus. It filters virus-containing respiratory droplets with a pore size of 60 to 140 nanometers. This is much smaller than pollen, dust and bacteria. Some cloth masks have built-in filters, but they don't work as well. While KN95 reusable adult cloth masks are approved...