Question about the "Hohner Accordion List"

[A.J. Walker]

Under "Type" of instrument, they're listed as one of:
Piano
Club
Knopf
HH

I understand Piano and Club. What are "Knopf" and "HH"

Thanks!

 

[JIM D.]

The word "Piano" is the Hohner name for it's PA models. "Knopf" means a button box, and "Club' means Diatonic models. The "HH" is for their harmonica products.