I opened a bottle of champagne but didn’t finish it before leaving town for over a week- when I got back I took this cap off thinking I’d be dumping the rest of bottle down the drain- but it was still bubbly! I wouldn’t make a habit of it but I was super impressed.It's rare that I actually have any champagne left ("leftover wine, what is that?") but occasionally need to save a bottle for the next day. I was skeptical that this would keep the fizz fresh, but it works like a charm and is much cheaper than similar champagne savers. Highly recommend!This item worked great! I got it to use for my beer that I couldn’t drink but actually used on the champagne first and it was nice!It is a lie, it does not seal, it does not stay closed, it is throwing your money away ?poor quality. champagne leaked. went back & purchased a more expensive and, hopefully, better quality.This champagne stopper is very easy to use! It stays secure on a bottle of champagne and my bottle maintained its carbonation even after a couple days had passed. Everyone needs a couple of these in their kitchen!MehWhen I first got the bottle sealer I thighs I was going to send it back because it feels like it doesn't seal the bottle well, but after using it for a while, I am pleased with how well it keeps the sparkling wine. Even after a week, it is still sparkling.