It has a single-reed mouthpiece attached to a short metal neck, similar to an alto clarinet. The heckelphone-clarinet is a transposing instrument in B with sounding range of D3 (middle line of bass staff) to C6 (two ledger lines above the treble staff), written a whole tone higher.
The Heckelphone-clarinet is a transposing instrument with a single-reed mouthpiece and a short metal neck, similar in design to an alto clarinet. It has a range that spans from D3 (middle line of the bass clef) to C6 (two ledger lines above the treble clef), written a whole tone higher than its base pitch.