What is N95 Respirator

What is the N95 respirator?
A: The N95 respirator is an air-purifying respirator (APR) certified by the National Institute for Occupational Safety and Health (NIOSH), otherwise known as a filtering facepiece respirator. N95 is not a name of a 3M product, but a filtering efficiency rating as tested by NIOSH.3M has several respirators that has this rating: 8210, 9010, 9105, 1860, etc. The 95 refers to the efficiency of the filtration medium of the respirator. Respirators are available in other particle efficiencies such as 99 and 100, and 3M has several products with these
filtering efficiencies.