Thanks again to Gary Kern, who allowed me to review this Penzel as well as the G. Penzel. This one appears to be much earlier. I am guessing this was made around 1920 or before.
Mueller's name is only visible on the right hand joint. I thought at first that this was just a Penzel because I missed seeing the faint Mueller stamp.
Barrel: cut to 60.7mm and the top tenon shortened also. I think the owner was playing with small bore brass instruments in the 1920s or so, and it is likely that this was in a military band. U.S. is stamped on the case.
Bore LH joint top: 14.6mm
Bore LH joint at bottom: 14.6mm
For this test, I pulled .4mm at the barrel and .2 at the center tenon, and I used a 64mm Ridenour barrel, since the original barrel is now way too short.
Intonation summary: The highest E and F and quite flat. Other fingerings could be used to make those in tune. This clarinet plays with what would have been professional level intonation when it was made. Now it is still good solid intermediate intonation.
Key work quality: Nice quality nickel plated keys. Note the left hand Ab/Eb and especially note the wonderful rollers for the right pinkie.
If the special ring finger key (top Eb/Bb key) lowers a tiny pad. This key can be added to lower the high register B and C, making them very nicely in tune. The left hand ring finger ring key makes it possible to play Eb/Bb with just 1 + 3. This is a very cool feature!
This clarinet is most appropriate for: Anyone who will enjoy playing a very unique antique clarinet with the extra left pinkie Ab/Eb key and left ring finger tuning key.