Rare 9 inch drivers with tweeter on frame in front of bass-driver dust cap.
Not the first time I find a good co-axial driver outperforms a good full ranger. E.g. Visaton B200, Fostex etc.
Peerless did not bother replying regarding driver parameters but sensitivity seems very high.
Original Jensen caps (which measure fine) supplied but have replaced them just in case. – see image.