... directly connect with filter. When in the environment of chemical or biological pollution, TF3D gas mask can effectively prtect ... and steam,sulfuric dioxide,chlorine,hydrogen sulfide,phosgene,nitrogen oxide,phosphorus and chloric organic,pesticide,poisonous smoke and fog ... and steam,sulfuric dioxide,chlorine,hydrogen sulfide,phosgene,nitrogen oxide,phosphorus and chloric organic,pesticide(SO2)13.330 Z ...