Perrygraf Concrete Pipe Assoc.of MI, Inc. Hydraulic Slide Rule for Desiign of Sewers

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Country of manufacture: USA,            Date of manufacture: >= 1958
Overall length: 33.1 cm,          Width: 12.0 cm.,           Weight: 72.4 gms.
Materials: cardboard shell with cardboard slide
Cursor: 5.0 X 12.0, wraparound plastic
Scales: 21, most specialized
Front: Flow [ Parts Full, Length of Sewer, Drop in Feet ] Pipe Diameter in Inches (for N = .011, .013, .015, and .024), Velocity [ Length of Sewer, Drop in Feet ] Pipe Diameter in inches (for N = .011, .013, .015, and .024)
Back: A [ B, CI, C ] D, K
Condition: C4-C5 (Minimal to normal use)
Came with: envelope/sheath; no writing on this

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