Cov khoom siv kab rov tav kuj tuaj yeem siv rau qhov hnyav-qhov cardboard pov tseg vim lawv muaj peev xwm thev dhau qhov hnyav dua thiab feem ntau muaj qhov ua haujlwm ntawm lub suab. Rau ob qho tib si kab rov tav thiab kab rov tav, qhov kev sib txig ntawm cov khoom siv yog siv cov txheej txheem hydraulic uas yog cov txheej txheem ua kom muaj zog, thiab ua rau muaj hluav taws xob tsawg dua thaum ua cov txheej txheem.
Cim npe nrov: tsis siv neeg tus ceev xwm, Tuam Tshoj, Hoobkas, cov chaw muag khoom, chaw tsim khoom, ua nyob rau hauv Suav teb
