The Wine Saver is a vacuum pump, which extracts the air from the opened bottle & re-seals it with a reusable rubber stopper. Place the reusable stopper in the bottle & extract the air from the bottle using the pump. A “click” sound tells you when you have reached the optimum vacuum level. The vacuum slows down the oxidation process which makes it possible to enjoy your wine again at a later date. Not for sparkling wine.