Vuam cov yeeb nkab tseem hu ua welded yeeb nkab, uas yog ua los ntawm cov phaj hlau lossis cov hlua hlau tom qab crimping thiab tsim, thiab feem ntau tsau ntev yog 6m. Vuam cov yeeb nkab hlau muaj qhov zoo ntawm cov txheej txheem tsim khoom yooj yim, ua haujlwm siab ntau lawm, ntau yam thiab cov yam ntxwv tshwj xeeb, cov cuab yeej siv peev txheej tsawg dua, tab sis lub zog dav yog qis dua cov yeeb nkab hlau tsis xeb.