The Vacu Vin replacement stoppers, used with the accompanying Wine Saver, a patented pumping system, ensure that your already opened wine bottles can be stored for longer. Simply insert the stopper into the bottle neck and use the pump to remove the remaining air. A "click" sound indicates that enough pumping has been done and the optimal vacuum has been achieved. This slows down the oxidation process, allowing you to enjoy the wine again later. The question of how often to pump is now a thing of the past. The unique, patented vacuum indicator signals with a "click" sound that the optimal vacuum has been reached.