The present application relates to a vacuum flask assembly (1). The vacuum flask assembly (1) comprises a vacuum flask (2) with a push-button lid (5). The push-button lid (5) is movable between an open condition and a closed condition, in which a sealing actuator (15) of the lid (5) is elevated when the lid (5) is in its open condition and retracted when the lid (5) is in its closed condition. The vacuum flask assembly (1) further comprises a container part (21) which is locatable over the lid (5) and is mountable to the vacuum flask (2). When the lid (5) is in its open condition, the container part (21) is configured to act on the sealing actuator (15) as the container part (21) is mounted to the vacuum flask (2), so that the lid (5) is urged to move from its open condition into its closed condition. The present application also relates to a container (3) for a vacuum flask (2) and a baby bottle kit.