Vuam caj dab flanges yog qhov yooj yim kom paub txog ntawm lub hub ntev tapered, uas mus maj dhau ntawm phab ntsa tuab ntawm cov yeeb nkab lossis haum.
Qhov ntev taper hub muab kev pab tseem ceeb rau siv nyob rau hauv ob peb daim ntawv thov uas muaj kev kub siab, sub-xoom thiab nce kub.