What is this part? (Transmitter bridge)

[allnumbedup]

Found in a box lot of phone stuff. I don't recognize this bracket but it is nicely engineered and marked. Any ideas?

[G-Man]

Found in a box lot of phone stuff. I don't recognize this bracket but it is nicely engineered and marked. Any ideas?

Transmitter bridge with diaphragm and other parts missing.

[G-Man]

Transmitter bridge with diaphragm and other parts missing.

Here is a jpeg showing an example of a complete transmitter:

[allnumbedup]

thanks for the effort and quick response. JC