Texture and material nonwoven fabric, flat, folded, with microfiltration, nose splint and strap, no bonded error BFE 98 -99.5%Respiratory resistance (mmH2O) Respiratory resistance (DP) is not greater than 9mmH2O Weight (g) : Not more than 10g Limited field of view Limited field of view not exceed 6% Acceptable limits of heavy metals Arsenic content (As) : 0.17mg/kg Lead content (Pb) : 1.00mg/kg Mercury content (Hg) : 0.12mg/kg Antimony content (Sb) : 0.10mg/kg Cadmium content Cd) : 0.10mg/kg