Combination clarinet. Nominal pitch: B♭/A.

https://images.is.ed.ac.uk/luna/servlet/iiif/UoEart~2~2~57871~102676/full/,150/0/default.jpghttps://images.is.ed.ac.uk/luna/servlet/iiif/UoEart~2~2~78170~184012/full/,150/0/default.jpg