“HH” Wooden slide rule

Data:

• Timber with plastic scale cover in leather look sleeve
• German text
• Looks like FC or?
• No name, but “HH” at back side
• See also Herman's Archive item 2613

Questions:

1. What is “HH”?
   HH is a known but obscure German maker A.A. Hoehler from Hohen Neuendorf — hence the HH company name. It looks like they only made one model, a Rietz fittingly called UNIVERSUM. David Rance
   See Rechenschieber Rietz Universum (translation) Leo van der Lucht, Jean Paul Hild
   Not to be confused with “KHH” See Wer waren Koch, Huxhold & Hannemann ? Leo van der Lucht