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- [United States National Bureau of Standards Metric Conversion Card]
- Conversion card issued by the United States National Bureau of Standards containing conversion information for length, area, mass (weight), volume, and temperature (exact). The front lists "Approximate Conversions to Metric Measures" and includes a continuum of temperatures at the bottom and a centimeter ruler along the right side (to 8 cm.). The back of the card lists "Approximate Conversions from Metric Measures" and includes an inch ruler along the right side (to 3 in.).
- [United States National Bureau of Standards Ruler]
- Ruler issued by the United States National Bureau of Standards. The front includes measurements in centimeters (to 15) and inches (to 6); there is text on the back comparing metric and customary units for length, volume, and weight.