Applicable to various bottle mouthsThe bottle stoppers is designed with a trapezoidal line, which is suitable for red wine bottles of 15-20mm bottle mouth sizes. Wine Stoppers for Bottles of Opened Wine4 Packs wine stoppers satisfy you for daily use or after weddings or parties. For the red wine that you can't finish drinking, just need one bottle stopper for your wine bottle, then you can easily keep your wine fresh. Keep your wine in a vacuumThe wine stopper has built-in vacuum pump. By pumping the vacuum pump, you can pump out the air in the wine bottle and keep it in a vacuum state, which can keep your red wine in fresh for long time Easy to useJust insert the wine bottle stoppers into the bottle mouth, then pump up and down the vacuum pump to extract the air inside, until it is difficult to pump, indicating that the wine bottle is already in a vacuum state. When you want to drink your red wine, just gently shake the wine stopper from side to side to pull out it.