The FED 1 rangefinder camera is a Soviet copy of the 1932 Leica and as such, uses the same M39 screw mount. The FED 1 is a bottom load 35mm camera, with separate viewfinder and rangefinder windows. As with most early FED cameras the film must be advanced prior to shutter speed selection. 

Make FED
Model 1D (type 8)
Year 1939-1941
Format 35mm
Shutter Cloth Shutter
Speed B,1/20 – 1/500
Lens Fed (M39 mount)
  1:3.5 f=50mm
Aperture 3.5 to 18
Focus 1m to 20m +∞
Light Meter No
Rangefinder Yes