| 摘要 |
A closure device, which may serve as a bottle closure or as a sink plug, or may constitute a container such as for an air-freshener material, comprises a base and a lid, formed by a resiliently deformable disc, centrally resiliently mounted on a bridge spanning the base and capable of flexing reversibly between two stable dished conditions, respectively an externally convex closed form and an externally concave open form. |
