CASE  :  Chrome plated, 33 mm .

BACK  :  Screw,  steel.

               S/N and the symbol of Helma ( helmet ) .

MOVEMENT  :  AS 1130  no name .

CASEBACK MARKINGS:  D. H.  only .

                           letters and numbers have the same size  ( 1 mm ) .

S/N  :  6 digits . Because the small number of watches recorded ( 6 ) it is not possible to define a range .

                          However , the observed watches had a S/N ranging from  006XXX  to  155XXX ,

                          The numbering is typical of Helma .

NOTE   : 

             1.  EDO was produced in Germany by  Ernest  DOhrman 

                  Probably, the use of Helma cases and  AS 1130 move to belive that EDO was an assembler only .

             2.  S/Ns are purely indicative .