Zingwe zomangira ndi zingwe zomwe zimakulungidwa kapena kumangidwa m'njira yoti zipange bumper yokhuthala komanso yoteteza. Zimalumikizidwa kunja kwa bwato kapena malo omangira kuti zisawonongeke ndi kugundana, komanso zimateteza maboti ndi malo omangira kuti asagwedezeke mosafunikira.