Bass clarinet extension
This is a tuning correction for the Selmer low Eb bass clarinet. The lower Eb and E of these instruments are already low at normal playing intensity mf (approx. -20 cents), the problem increases when you need to play more loud, at forte. The non-invasive solution is to extend the instrument and relocate the last tone hole.
(Of course, it is possible to make this part longer and add other tones D, C# and C.)