Uses one 8mm, 9mm on the upper joint. Lower 2 x 12mm, 15mm, 2 x 17mm, 1 x 16 or 16.5.
The key work is extremely sturdy. This has almost the same key work as the Forte.
Keys: The right hand bridge has little triangular extensions on the sides.
The register key has this shape near the pad cup, as does the Forte clarinet.
I picture these things because we see these same shapes on some French “stencil” clarinets, leading me to think that they got their keys from this company.
Note how thick and blunt the pinkie keys are at the edge, as they are on the Forte.
This is obviously a forerunner of the Forte clarinet, which is also Czechoslovakian made.
I am therefore comparing its intonation with my early-model Forte.
Woah there! The person playing this clarinet will never be accused of playing flat!
It seems clear that the Forte is a great improvement over this one.
The new owner should get a cheap, standard 66 mm barrel without delay.
Finally, the left pinkie levers are sturdy, but not pin in hole style: