Nakuba zombili zinomumo "C", imininingwane yazo yesigaba esiphambene kanye namandla esakhiwo kuhluke kakhulu, okuthinta ngqo amandla azo okuthwala umthwalo kanye nezikophu zokusetshenziswa.
Ingxenye ephambene ye-C Channel iyi-isakhiwo esihlanganisiwe esishisayo nesigoqiwe. I-web yayo (ingxenye eqondile ye-"C") iwugqinsi (ngokuvamile i-6mm - 16mm), kanti ama-flange (izinhlangothi ezimbili ezivundlile) abanzi futhi anomthambeka othile (ukwenza kube lula ukucubungula okushisayo). Lo mklamo wenza ingxenye evundlile ibe nokumelana okunamandla kokugoba kanye nokuqina kokugoba. Isibonelo, isiteshi esingu-10# C (esinokuphakama okungu-100mm) sinobukhulu be-web obungu-5.3mm kanye nobubanzi be-flange obungu-48mm, obungathwala kalula isisindo sezitezi noma izindonga esakhiweni esiyinhloko.
Ngakolunye uhlangothi, i-C Purlin yakhiwa ngokugoba okubandayo kwamapuleti ensimbi amancane. Ingxenye yayo evundlile "incane kakhulu": ubukhulu bewebhu buyi-1.5mm - 4mm kuphela, kanti ama-flanges mancane futhi avame ukuba nama-fold amancane (abizwa ngokuthi "ama-reinforcer ribs") emaphethelweni. Lezi zimbambo zokuqinisa zenzelwe ukuthuthukisa ukuzinza kwendawo kwama-flanges amancane nokuvimbela ukuguquka ngaphansi kwemithwalo emincane. Kodwa-ke, ngenxa yezinto ezincane, ukumelana kokugoba okuphelele kwe-C Purlin kubuthakathaka. Isibonelo, i-C160×60×20×2.5 C Purlin evamile (ukuphakama × ububanzi be-flange × ukuphakama kwewebhu × ubukhulu) inesisindo esiphelele esingaba ngu-5.5kg ngemitha, okulula kakhulu kune-10# C Channel (cishe u-12.7kg ngemitha).