Superb Build Quality - An absolute bar keepers friend, our electronic wine saver vacuum pump is made using high quality and durable food-grade silicone on the inside and food-grade ABS on the outside. This makes each of our wine bottle stoppers non-toxic and safe to use. It also allows you to enjoy an open bottle of wine much longer without compromising its flavor. Keeps yours Wine Fresh - Once applied, our wine pourer and stopper becomes airtight and prevents oxidation by sucking the air out of the bottle. Our wine saver vacuum pump will help preserve the flavor of an open wine bottle for weeks instead of just days. Our wine stoppers are a practical and functional solution for any home, bar, or restaurant. Our electronic wine toppers can fit bottles with an outer diameter of 29mm0.5mm and an inner diameter of 20mm0.5mm. Absolutely No Leaks; Spills - Once attached to the mouth of the bottle, our electronic wine stopper vacuum mechanism automatically creates an air-tight seal and checks the air pressure within the bottle. Once negative air pressure exceeds -0.01 MPA, our smart wine preserver system automatically performs repeated pumping to ensure a consistent vacuumed state. Using our wine stopper ensures that the content within stays fresh and also prevents leaks if the bottle is not properly stored. Super easy to use - All you need to do is press down one of our rubber wine stoppers into the bottles mouth. A digital blue breathing light will then appear to indicate a vacuum seal. Once the bottle is tilted to 45 degrees, the anti-fall function of our wine pump is triggered and a red light flashes, allowing you to pour its contents. The wine bottle stopper vacuum sensor will then automatically turn back on once the bottle angle again below 45 degrees. Like I said, super easy