Sealable closure and closed container

A lid includes two parts each having a sealing surface 14, 15, each movable between open and sealed configurations. Each part can include a circular disc portion 1, 18 and a frusto conical portion 2. Depression of the disc portion can flatten both frusto conical portions, increasing their diameter and urging both sealing surfaces against a container walls inner surface. The upper part can have a flange to overlie the top of the container rim as well as engaging the containers inner walls. A gripable knob 7 can be pushed or pulled to seal or release the lid. Alternatively the actuator could be hydraulic, magnetic, pneumatic and/or automated. The grip can be flush with the lid when sealed. one of the sealing surfaces can contain silicon and the other part can be formed of a different material. The lid is preferably horizontal and can include security markers to indicate tampering. The container can contain liquid.