Thaum peb tsim thiab tsim cov hlwv ntim (cov khoom siv ntim yas clamshell, peb muaj peb yam pwm, peb muaj peb yam pwm pwm, cov hauv qab no yog cov yam ntxwv ntawm cov pwm sib txawv:
Gypsum pwm: qhov contour ntawm cov pwm ua tiav los ntawm cov av nkos, thiab cov qauv siv hluav taws xob zoo dua qub
Tooj liab pwm: nws tau siv rau huab hwm coj ntau lawm, qhov khoom siv tooj liab tau ua kom tau raws cov qauv, peb yuav xaiv tooj liab pwm.
Aluminium pwm: nws tuaj yeem siv rau hauv cov qauv ua thiab huab hwm coj muaj rau cov tshuaj tua kab mob loj, feem ntau yog siv rau cov neeg qhua tuaj yeem siv tau ntau dua, peb pom zoo xaiv txhuas cov pwm.
Nws tsis muaj teeb meem yog tias koj tsis paub yuav ua li cas xaiv cov pwm, thov koj xav tiv tauj peb, peb yuav ua pwm raws li koj cov khoom yuav tsum tau!
