A wine bottle stopper is a device used to seal an open bottle of wine, preventing air from entering and preserving the wine's flavor and aroma. These stoppers come in various materials, including cork, silicone, and metal, and are designed to fit snugly in the neck of the bottle. Using a wine bottle stopper can extend the life of an opened bottle, allowing you to enjoy the wine over several days. Some stoppers even feature vacuum mechanisms to remove air, further enhancing preservation. Proper storage with a stopper helps maintain the quality of the wine until you're ready to drink it again.