Muaj tshuab, cua sov thiab cua txias tshuab, tshuab cuab yeej.
Feem ntau yog siv rau hauv qhov chaw qhuav, ntub dej thiab ntub dej (nrog rau cov dej-roj sib tov), tab sis tsis yog siv rau sab nraum zoov.
Rau kev txhim kho ruaj khov nyob rau hauv nruab nrab cov khoom siv thauj khoom nruab nrab, thiab cov ntawv thov nrog qee zaus flexing ntawm dawb, tsis tu ncua rov ua haujlwm tsis muaj tensile load lossis kev taw qhia yuam kev.