Cov iav iav yog ib qho tsawg kawg yog ib tus hniav ua tiav (xov) nyob ib ncig ntawm cov kab mob cab.Qhov kev siv hniav iav yog siv rau ntawm ib qho ntawm 90 ° rau txhua lwm yam thiab pw saum dav hlau.
Cab zogBelon RaugCov Ntawv Thov:
Revenucers ceev,Antireversing iav li ua rau feem ntau ntawm nws tus kheej lub xauv cov cuab yeej, tshuab cov cuab yeej, cov pob zeb saw, hluav taws xob tsim hluav taws xob thiab lwm yam