紅酒樽口上黑色的東西??

那個是數碼防盗標幟晶片，類似條碼 (bar code)之類的保安或庫存系統。

2009-03-01 00:39:25 補充：
用刀仔

For security reason. For those expensive wine, Parkn shop will put such black cover onto the bottle of wine. THere will be an alarm if you pick the bottle out of the supermarket without paying it.