Unitrex 91PM Handheld Electronic Calculator

This handheld electronic calculator has a gray and black plastic case with an array of twenty-three square plastic keys. These include ten digit keys, a decimal point key, a total key, four arithmetic function keys, four memory keys, a percentage key, a clear key, and a clear entry key. Right of the top three keys is an on/off switch. Behind this is an eight-digit red LED display. A mark behind this reads: UNITREX 91PM.
A power jack is on the right side near the bottom.
The back of the calculator has a compartment for a nine-volt battery at the top. A sticker below this reads: ELECTRONIC CALCULATOR (/) DC 9 VOLT (/) USE 1 PIECE 9 V BATTERY (/) MADE IN HONG KONG.
[Advertisement], Chicago Tribune, January 30, 1977, p. M1. Calculator on sale for $8.88, regularly $9.95. “Save $2”!
Currently not on view
Object Name
electronic calculator
date made
ca 1977
Eiko Business Machine Company
Physical Description
plastic (case; keys material)
metal (circuitry material)
paper (sticker material)
overall: 1 in x 2 in x 5 3/8 in; 2.54 cm x 5.08 cm x 13.6525 cm
place made
Zhonghua: Hong Kong
ID Number
catalog number
accession number
See more items in
Medicine and Science: Computers
Handheld Electronic Calculators
Computers & Business Machines
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of John B. Priser
Additional Media

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