Electret mic help!

Hi. I got an electret capsule today, and the underside looks like the attached image. You can see, one of the pads appears to link to the metal caspule which it is contained in. I really need to know which of these is the positive and ground/negative!

**broken link removed**

That is the part, but I can't tell anything from that image.

The pad connected to the case is negative. The other is positive.

Thanks