Prolonged contact to oxygen slowly deteriorates the flavor and bouquet of your wine. To prevent this, simply insert the stopper into your bottle and pump out the excess air with the AirLOCK™. Freshness is sealed in when the red indicator drops down. Keeps wine fresher than generic stopper. HOST® AirLOCK™ Wine Preserver Pump features an ergonomic handle making it easy to remove air from your wine bottle.