Double Bass Pickup identification

[bassbowy]

I recently saw a bass with a interesting pickup that I want to identify. Basically someone cut out four small rectangular notches at the top of the bridge and inserted four metal pieces in it's place. Anyone seen anything like this?

 

[Francois Blais]

Sounds like the Barbera system.
This? : Electric Upright Bass Pickups

 

[bassbowy]

Thanks so much. I do believe I saw BTS stamped on the bridge so I think this is it.