Sab nrauv rearview tsom iav yog cov khoom siv mounted ntawm ob sab ntawm lub tsheb sab nrauv, feem ntau ua haujlwm pab tus neeg tsav tsheb saib xyuas txoj kev hauv qab thiab sab ntawm lub tsheb. Feem ntau yog tsim los ntawm daim iav saum npoo, vaj tse, thiab kev hloov kho, lawv ua zoo li ob "pob pob ntseg" tas li muab tus neeg tsav tsheb saib ntawm thaj chaw tom qab lub tsheb. Cov iav sab nrauv niaj hnub no feem ntau sib xyaw ua ke xws li cov teeb liab tig thiab cov cua sov / defogging, ua haujlwm tseem ceeb hauv kev tsav tsheb ntse.
Cov iav no feem ntau siv cov iav convex (los yog dual- iav convex). Convex mirrors tsim cov duab me dua li cov khoom siv tiag tiag tab sis muab qhov dav dav ntawm qhov pom dua li cov iav tiaj tus - zoo ib yam li qhov dav - lub kaum ntse ntse lub koob yees duab lens - yog li txo qhov muag tsis pom kev. Dual- qauv curvature muab qhov zoo ntawm ob qho tib si convex thiab tiaj tus tsom iav: sab nrauv nta curvature siab kom nthuav dav ntawm qhov pom, thaum lub sab hauv nta qis curvature kom paub meej qhov kev pom, ua kom cov npoo ntawm qhov yuam kev tsis pub dhau 5%.