 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 instrument is not to be confused with the heckel-clarina, also a very rare conical bore single reed woodwind by Heckel but higher in pitch and made of metal, nor with the heckelphone, a double reed instrument lower in pitch.