This is the early Version of the Zeiss Ikon Model A 520 in 4 1/2 x 6 format, 16 pictures to a roll of 120 film. The viewfinder is a simple frame and the film number indicators have no light cover. The shutter release is on the shutter itself.  It is covered in real leather and has the top of the line Carl Zeiss Jenna Tessar f3.5 7cm lens.

Zeiss Ikon  Model "A" 520 Ikonta