Abstract: A foldable reflector which includes a plurality of rib assemblies mounted around a base. The axes around which the ribs assemblies pivot lie in substantially the same plane. Each rib assembly has a rib portion and an offset member. The rib portions, which deploy flexible reflective material, lie substantially forward of the plane in both open and closed positions. The offset member have attachment points which extend to the forward side of the plane when the rib assemblies are in the closed position, and to the back side when they are in the open position. Elastic means extending between the attachment points of adjacent offset members bi-stably hold the rib assemblies in both the open and closed positions. A lock plate with radially extending portions locks the rib assemblies in the open positions when the lock plate is rotated to a position wherein the radially extending portions obstruct the pivoting of the ribs.