Good used tweeter from Infinity Quantum 3 speaker.
Tested, working perfectly.
8 ohm
1 1/2 inch diameter dome
5 1/8 inch frame.
4 1/8 inches hole to hole mounting
1 1/4 inch deep setback.
This may be a replacement driver. The speakers have been rebuilt.
The other tweeter is labeled Audax. The part number on this one seems like a Polydax number. Maybe Peerless.