Antiox Carbon Filter Wine Stopper by Franmara This patented system avoids oxidation of wine inside an opened bottle. The silicone based stopper contains an active carbon filter inside. This effectively interrupts oxygen interacting with the wine. Made in Spain and recommended by the Spanish Academy of Sommeliers. Equipped with a day marker. This consists of a metal ring around the circumference to be turned to the day the wine was closed (31 day indications). For optimal performance the bottle should be stored in an upright position Stands 1-7/8 H x 1-1/2 dia.