Electronic Vacuum Wine Preserver with 3-Day LED Day Indicator and Integrated Vacuum Sensor Effortlessly keeps unfinished bottles fresher, longer to preserve the original taste, aroma and color Automatically creates a vacuum seal Built-in sensor pumps out air and regulates the inner vacuum 3-Day LED day indicator: Green LED for days 1-3, yellow LED for days 4-6 and red LED for Days 7+ Powered by only 2 x AAA batteries (not included)