A cover for sealing a container and preferably containers for a well plate. The cover is comprised of at least a top layer and a bottom layer structured in a way to form a recloseable aperture. Preferably, each of the layers comprise a recloseable aperture structured as flap, damper, baffle or butterfly valve respectively, wherein the recloseable apertures are arranged on top of each other. In a preferred embodiment of the invention a third moveable layer is arranged between the top and the bottom layer. By moving the middle layer, the aperture in the cover can be closed.