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Diwa No. 601

• Type: Closed Body Rietz
• Size: 5 Inches / 13 cm
• Material: Plastic
• Scales:
  • Front: 5 inch / K A [ B CI C ] D L
  • Back: 13 cm [ S ST T ]
• HvH: best match is 3254

Sewn leather case, instruction sheet, box (badly blown out). Inch and centimeter scales. S and T scales read against C. Tangents can only be read directly to 45 degrees. The runner is glass, mounted in chromed steel, and has added hairlines for circle area calculations.

This is an advertising specialty item, impressed for Union Carbide. Before 1962, I'm guessing mid 50's.