F. W. Breithaupt & Sohn (Kassel) is an old German company with a long tradition which delivered many compass types to the industry (mines) and the armies. It was created in 1767 by Johann Christian Breithaupt (born 23 June 1736, died in 1800). He was later designated Hofmechanikus (chief engineer) of Landgraf Friedrich IInd of Hesse-Cassel in 1768. (Source Compassmuseum.com)
This fine compass was made of aluminium, with some brass parts.