This sextant was made for the German navy and was probably used during World War II. An instruction label in the box is dated "Januar 1945." Like the SOLD sextant made by Plath, this one has a gyroscopic artificial horizon, and an integrator attachment that averages several observations taken in quick succession. The Smithsonian purchased this example in 1979 from Laboratorium Dr. Justus Rosenhagen, a scientific instrument maker in Hamburg who had built up a collection of historic instruments.
Ref: Gyro-Sextant, Model FR 3.
C. Plath 1862-1962 (Hamburg, n.d.), pp. 112-116.