That's an awesome page.
Great work and thanks.
I've got a P10XX A clarinet. The speaker bush is a little different and it has a small hole in the bell to sharpen the low notes. My repair man said he'd never seen one on an A clarinet.
P Series - Centered Tone series - identifiable by a large hexagonal speaker bush (the body octave hole). Benny Goodman made these instruments famous. The Centered Tone bore changed through the years. Initially it was a cylindrical bore of 15.00mm to 15.10mm. The barrel was 66mm long and had a slightly wider 15.15 bore.
After the Q series the bore changed and continued on through the Series 9. The Q series brought along the change of longer upper and lower joints of approximately 5mm.
If you click on the brochure for a full page view you will notice the options you had with these clarinets. And another interesting note - the mouthpiece in the picture is a lower emblem mouthpiece - not the oval table (which has a middle body crest emblem - see the Mouthpiece gallery for pictures of these). So .. one would assume the Ovals came AFTER the introduction of the CTs.