A container top comprising a container top member comprising tracks over an upper surface thereof and a sealer sealing an opening thereof; and a slidable member having a sealing mechanism, the slidable member being slidable through the tracks and positioned such that sliding of the slidable member over the tracks to one direction unseals the sealer, forming an opening over the container top member, in the initial opening thereof and wherein sliding the slidable member back to its original position over the opening formed thereby covers and seals the opening. The opening formed by the unsealing of the sealer can be re-sealed at will by the sealing mechanism of the slidable member. The sealing mechanism may be for example a sealing material coating strip located over a periphery of the slidable member or the physical configuration of the slidable member periphery edges.