Vacu Vin Vacuum Wine Saver Pump with 1 Stopper SetThe Wine Saver is a vacuum pump, which extracts the air from the opened bottle and re seals it with a reusable rubber stopper. Place the reusable stopper in the bottle and extract the air from the bottle using the Wine Saver 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. The question "how often do I have to