Flight Computer кнп-57 USSR Soviet Air Force 1957

This is an authentic кнп-57 Soviet Flight Computer, essentially equivalent to the western design E6-B.  The front compass side is of a normal design, but the reverse side calculator combines a traditional slip stick with a wide array of useful aviation calculations.  It is marked as having been The device is constructed of a very stiff durable plastic which almost feels like ivory. Measures ~10 in x ~4.5 in.