Tom qab ua haujlwm raws li lub tshuab tau ntau xyoo, koj yuav tsum tsis paub lub ntsiab lus ntawm cov ntawv lo ntawm cov ntsia hlau, puas yog? Cov qib kev ua tau zoo ntawm bolts rau steel qauv kev sib txuas tau muab faib ua ntau tshaj kaum qib, xws li 3.6, 4.6, 4.8, 5.6, 6 ....
Nyeem ntxiv