Acid Reducing Ring? - does it exist?!

[lizardbrains]

I work at a large-chain home supplies store, and today someone asked me if we carry the following: a thing that goes around a wine bottle to reduce the acidity of the wine as well as to age it. I had no idea what she was talking about (but I am picturing something similar to the insultated thing that goes around the bottle to cool it). I would assume they don't exist, but she says her friend has one, but doesn't remember where she bought it.

Do any of you know what this lady is talking about? Have you used it? Where did you buy it? I'm baffled!