Texas Instruments TI - 2550 - Ingenious Mid-1970's Electronic Calculator!

Texas Instruments has a longstanding reputation as electronic calculator innovators. An industry leader, TI, invents the world's first handheld electronic calculator. In 1972, TI'S first handheld calculator is made available for the retail market.
There have been many advances since.
The TI - 2550 is an important entry into this company's storied history.
TI - 2550 Details:
Power - 4 x "AA" Batteries
Date Made: 1974 - 1976
Measurements: 1 3/4 inch x 3 inch x 6 1/2 inch
Texas Instruments Incorporated, (TI), Dallas, Texas, U.S.A.