Hais txog cov qauv kev lag luam, hlau thawb- mus rau- txuas fittings yuav tsum ua raws li cov qauv nruj nruj thiab kev nyab xeeb tshwj xeeb. Cov qauv no tsis tsuas yog tswj hwm cov kev xav tau tseem ceeb- xws li cov khoom siv, qhov ntev, thiab kev ua tau zoo- tab sis kuj qhia txog cov txheej txheem tsim khoom thiab cov txheej txheem kuaj. Yog li ntawd, thaum xaiv hlau thawb- rau- txuas fittings, cov neeg siv khoom yuav tsum xyuas kom meej raws li cov qauv tsim nyog los xyuas kom meej cov khoom zoo thiab kev nyab xeeb.
