Filtering facepiece respirators (FFR), which are also called disposable respirators, are subject to various regulatory standards around the world (see examples below). Certain required physical properties and performance characteristics are specified in order for respirators to claim compliance with the particular standard. N95/KN95/FFP2 respirators are commonly recommended by health authorities during pandemic or emergency situations. They are not exactly the same, but respirators certified as meeting these standards can be expected to function very similar to on another.