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One of the most popular IR rules was made by General Electric. GE was a major player in defense electronics, going back to WWII radar systems. GE sold its military electronics operations to Martin Marrietta in 1992. The slide chart is made of an outer body in plastic and an inner cardboard. slide.
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This is an older version of the same rule, also made for GE. It is all cardboard, and was made by Perrygraph.
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This is the Perrygraph IR slide rule as sold by IRIS.
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Here are the directions distributed with this rule.
This is the same Perrygraph rule, packaged for distribution by Judson.
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The Judson rule was pachaged in a cardboard folder that included instructions and examples.
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