3.Elliptic tube: elliptic tube yog ib yam khoom tshiab tau qhia nyob rau xyoo tas los no.Piv nrog lub voj voog, lub raj elliptic muaj qhov tshwj xeeb zoo siab ua haujlwm.Txawm li cas los xij, vim tias cov raj elliptic uas twb muaj lawm yog ua los ntawm galvanized daim kab xev, nws cov kev ua haujlwm tiv thaiv corrosion tsis zoo rau cov raj raj.
4.Profile Steel: nws yog siv rau sab saum toj ntawm lub tsev cog khoom ntse los tsim ib lub thav duab steel.Nws muaj qhov zoo ntawm cov nqi qis thiab kev ruaj ntseg tsis zoo piv nrog cov yeeb nkab square.Nws yog siv rau hauv cov cheeb tsam uas tsis tshua muaj kev ntxhov siab thiab kev tiv thaiv corrosion.