Daim npog ntsej muag no tsim nyog rau cov xwm txheej uas raug cov ntshav thiab / lossis cov kua dej hauv lub cev tsis muaj kev pheej hmoo.
Qhib qhov loj dua rau qhov ua pa txias dua;
Cov dej resistant txheej txheej;
Mos thiab number case dawb sab hauv txheej;
Kev tiv thaiv 3 txheej kev tsim kho;
Ntxiv ntev thiab yooj yim kho aluminium nosepiece kom haum zoo dua;
Mos thiab latex-dawb elastic bands;
Fiberglass-dawb;
Bacterial filtration efficiency 299%
