CONCEPT 24 distributed by Zayre Corp.

Date of introduction:  August 17, 1975 Display technology:  Fluorescent
New price:  SRP $24.88 Display size:  8
Size:  5.3" x 3.3" x 1.1"
 135 x 85 x 28 mm3
Weight:  4.8 ounces, 140 grams Serial No:  19024
Batteries:  4*AA Date of manufacture:  
AC-Adapter:   Origin of manufacture:  Japan
Precision:  8 Integrated circuits:  NEC uPD276C
Memories:  1    
Program steps:   Courtesy of:  Charlie Hartman

Zayre Corporation was founded in 1956 by Stanley and Sumner Feldberg in Hyannis, Massachusetts as a discount department store chain. Zayre launched already in August 1975 the CONCEPT series of portable electronic calculators with the introduction of their first CONCEPT 24, manufactured by Eiko Business Machines in Japan. Eiko Business Machines is in North America better known for it's Unitrex brand (Thanks Robert).

This rare CONCEPT 24 calculator was soon replaced with the 2nd design of the CONCEPT 24, based on an unknown calculator manufactured in Japan and identical to the more common Craig 4524.

The Zayre CONCEPT Calculator Series culminated in June 1976 with the introduction of the Texas Instruments CONCEPT I, CONCEPT II, and CONCEPT III calculators based on the TI-1200, TI-1250, resp. SR-16 II but disappeared already in August 1979 with the clearance sales of the CONCEPT COMPACT calculators.

Fellow collectors - if you own a Zayre CONCEPT calculator,  please report us the serial number and date code from the back of the calculator for our Database.

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If you have additions to the above article please email:

Joerg Woerner, February 2, 2010. No reprints without written permission.