Cov xim zoo nkauj coated steel phaj yog siv los ua cov txheej txheej saum npoo, galvanized steel sawb yog siv los ua cov ntug sealing chav thiab txhawb cov ribs, ya raws-pov thawj iav magnesium phaj yog siv los ua cov txheej txheem tseem ceeb, pob zeb wool yog siv los ua cov txheej txheem sab hauv. , uas yog tsim los ntawm pressurizing, cua sov thiab lwm yam txheej txheem.Nws muaj kev sib khi zoo thiab kev tiv thaiv hluav taws kub.