The FED-4 is a 35mm film rangefinder camera made in Russia by FED and produced between 1964-80. Its main improvement over the FED-3 is its added uncoupled selenium meter, with a window in front of the speed dial.

This is a Model 4b which dates from between 1969 and 1976. It is based on a 1930s German Leica rangefinder and shares the same L39 mount. It has a 53mm f/2.8 Industar-61 lens. The serial number is 112573.

This is quite a complex beast and using the camera requires some care: in particular the shutter speed can only be changed when the camera is wound on. The manual for the FED-4 is here:

https://www.cameramanuals.org/russian_pdf/fed_4.pdf