N99 Mask N99 high filter efficiency dust mask 1. NIOSH N99 dust mask, TC No: 84A-8146 2. High filter efficiency: at least 99% efficiency for oil-free particulates Pack of 10 pieces per box, lightweight respirator mask, easy to breathe; free indoor and outdoor maintenance; recommended to keep in the... High filter efficiency: at least 99% efficiency for oil-free particulates the so-called civil anti haze masks on the market have been lack of standard specifications. Many masks use "filter efficiency" to express their anti haze performance, and often call themselves "filter efficiency is more than 90%". In fact, the filtering efficiency only refers to the filtering effect of the filter cloth material, which is the core part of the mask, and does not represent the protective effect of the mask, because the mask still has the problem of sealing. Even if the filtering effect of the filter cloth can reach 99%, if the sealing is not good, the protection ability of the mask will be greatly reduced.N99 Mask website:http://www.fupinghealthcare.com/n99-mask/