The requirements of KN type masks on filter materials are that the materials in direct contact with the face are not harmful to the skin and the filter materials are not harmful to the human body.
Izidingo zamasks wohlobo lwe-KN ezintweni zokuhlunga ukuthi izinto ezixhumana ngqo nobuso azinabungozi esikhunjeni futhi izinto zokuhlunga azilimazi emzimbeni womuntu.