ukko contact mics, Anyone ever used them?

[rockironwebb]

I was just looking around the web at stuff that I can't afford and saw these UKKO contact mics. I was a little intrigued by them. I'm sure there are pros and cons. Just wondering if anyone has used these or something similar?

B-Band Ltd - UKKO By B-Band

 

[saads]

Looks to me like it would pick up a lot of the vibrations off the shell. I think the sound of the stick hitting the skin is something that needs to be captured, I don't see that happening with these. They look pretty neat though.