This "modern Slide Rule" / Proportional Scale  was bought in
Summer of 2008 in an Art Shop on the USA West Coast for only
$ 6.50  - It is still used in  "Graphic Oriented Trades" ...

C-THRU® RULER COMPANY, Bloomfield, CT / USA           (2008)

... M O R E :   Different versions  in original packages ...

SCALE-DIAMETERS:  PS-79 = 6" / 12.5 cm ;  PS-69 = 4" / 10 cm

impressum:
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© C.HAMANN    http://public.BHT-Berlin.de/hamann    08/09/08