Nrog optically ntshiab, tiv thaiv pos huab;
Qhib qhov loj dua rau qhov ua pa txias dua;
Cov dej resistant txheej txheej;
Kev tiv thaiv 3 txheej kev tsim kho;
Ntxiv ntev thiab yooj yim kho aluminium nosepiece;
Mos thiab latex-dawb elastic bands;
Fiberglass-dawb
