I use it since 1985 in position on a bridge customized strat unmarked.
It is a type of micro-sized humbucking a single coil.
One of the first microphone of this type, more powerful than the Fender, but made the same ideal position to bridge the time.
This microphone has been the subject of a collaboration between Bill Lawrence (installed in Germany at the time) and a falling out with Gibson.
This microphone is unfortunately no longer available (Order 1986), very rare.
Was also a product Humbucking, the L500.