Black MIR-1 Grand Prix Brussels 1958 2.8/37mm, M42 Mount 

sold as is in the photo!

Focal length, mm: 37;

Relative aperture: f/2.8 ;

Diaphragm scale from 2.8 to 16 ;

Mounting: M42 x 1mm, Focusing from 0.7m;

Filter mount M 49 x 0.75 mm;