Ntawm cov hlau thoob ntiaj teb, 50 mus rau 60% yog ua los ntawm cov ntawv hlau, feem ntau yog cov khoom tiav uas tau stamped thiab nias. Lub cev ntawm lub tsheb, lub tshuab hluav taws xob, lub tshuab hluav taws xob ntawm lub tshuab boiler, lub casing ntawm lub thawv, cov tub ntxhais hlau silicon steel ntawm lub tshuab hluav taws xob thiab cov khoom siv hluav taws xob, thiab lwm yam yog txhua yam stamped thiab ua tiav. Kuj tseem muaj ntau qhov chaw stamping hauv cov twj paj nruag, cov khoom siv hauv tsev, chaw ua haujlwm dulls, cov tais diav ntim khoom thiab lwm yam khoom siv.