Abstract: A ring mechanism for holding loose-leaf pages has an elongate housing having a central portion and longitudinally extending sides on opposite sides of the central portion. Hinge plates are supported by the housing for pivoting movement. Rings for holding the loose-leaf pages, each include a first ring member and a second ring member. The first ring member is mounted on and moveable with one of the hinge plates relative to the second ring member between a closed position and an open position. The housing has an opening extending laterally inward toward a center of the housing for receiving one of the first ring members. The housing has a vault-forming portion at the inner margin of the opening. The vault-forming portion of the housing is spaced from a longitudinal centerline of the housing and raised above longitudinally adjacent portions of the housing spaced the same distance from the centerline.