hooya Stainless Steel Wine Stopper - Super Easy to Keep Your Best Wine FreshSet of 4 EASY & EFFCIENT EASIEST several 'PUMPS' with palm removes air from the wine bottle and creates an airtight vacuum that preserves wine for up to 30 days, prevents the oxidation process that is responsible for the deterioration of wine. LOWER BOTTOM POSITION(1/2" working lowest, 1" initial) on the stopper would indicate the airtight vacuum has been established, air can't get in and wine won't break out. Saving wine has never been easier. PREMIUM STAINLESS STEEL SHELL is highly durable for years perfect use. All-in-one vacuum wine bottle topper. Creates an airtight vacuum without a separate pump! SCREW TOPS AND SPARKLING WINE are not included on most wine bottles. Fits standard wine bottle necks.