Graphic Calculator Company Boiler Efficiency and BTU Cost Calculator

Country of manufacture: USA,            Date of manufacture: >= 1950
Overall length: 21.5 cm,          Width: 5.5 cm.,           Weight: 24.8 gms
Materials: Plastic and cardboard
Cursor: No cursor
Scales: specialized
Condition: C5 (Signs of Normal Use)
Came with: Brown leather slipcase (w/hole in leather), labelled "Nashville Coal Co. of Louisville"