CASE : Chrome plated , 34 mm .
BACK : Screw , steel .
Outside shows the S/N only . Inside is punched a number .
MOVEMENT : Buren Grand Prix Cal 410 .
The Company name is punched on the ratchet wheel .
Most of the movements have separate wheels bridges . However , some watches have been detected
with a modified Cal 410 ( single wheels bridge ).
PUNCHING : D.H. only .
Letters are larger ( 2mm ) than numbers ( 1mm) .
S/N : 4 or 5 digits .
three batches can be assumed from the number of recorded watches ( 74 ) .
– 4 or 5 digits . Range could be 80XX / 166XX ;
– 5 digits . Range could be 223XX / 273XX ;
– 5 digits . Range could be 291XX / 298XX .
NOTE : Batches and S/Ns are purely indicative .
Standard movement “Grand Prix 410”