Concise Ruler Circular Slide Rule No. 300 100829 Made IN JAPAN 110mm

Concise Ruler Circular Slide Rule No. 300 100829 Diameter (approx.) 110mm F/S

Concise Ruler Circular Slide Rule No. 270N 100812 F/S w/Tracking# New from Japan

Concise Ruler Circular Slide Rule Metal Weight Calculator 96mm Engineering

Concise Ruler Circular Slide Rule No.300 100829 110mm

Very rare Logarithmic Ruler KL-1 Round Lineup Calculator Slide Rule USSR 91.V