What isthis part?

[SlicRic]

What is this part?

Hi,
I was pulling apart a walkie talkie to do some modifications on it and came across an odd part, I found the microphone lead, there was only a single wire, I then noticed that the mic was mounted on a paper backing, so I pulled the paper and instead of finding an ordinary mic I found a small part, about 3mm circular, it had a brass outside coating and a small dolop of metal that resembled lead in the middle, the paper I mentioned earlier actually has a coating of foil on the side of the part, this foil and the mic wire have continuity. Does anyone know what this is?
Thanks SlicRic

 

[flat5]

Can you provide a picture?

 

[SlicRic]

Thanks for your help, the part is actually a ground connection, the speaker actually doubles up as the microphone in this walkie talkie

 

[flat5]

Not uncommon, I'm sure.