Vintage 1974 Penn State PSU Memorabilia Army ROTC Conversion Slide Rule - 70s

Vintage 1974 Army ROTC Metric Conversion Slide Chart

Vintage 1974 Paper Metric Conversion Slide Chart Army ROTC advertising NOS

1974 Perrygraf 3M METRIC MASTER Calculator Slide Rule Conversion Chart

Vintage 1974 US Metric Converter Slide Ruler Conversion Chart - USA Army Guard

American Slide-Chart Metric Conversion Chart NJ National Guard 1974 Illinois

Vintage Metric Master Promo Metric Conversion Slide Rule Chart