Abstract: A closure device attachable to a fluid vessel, the closure device comprising a fluid passage and a valve comprising a valve member. The valve member is moveable between an open position and a closed position wherein fluid can exit an attached fluid vessel in the open position and is prevented from exiting an attached fluid vessel in the closed position. The closure device is moveable between a first and second configuration. The fluid passage is obstructed by the valve member to prevent fluid from exiting an attached fluid vessel when the closure device is in a first configuration. In the second configuration, the valve is moveable between the open and the closed position.