This handheld electronic calculator has a metal and plastic case and an array of twenty-five square plastic keys. In addition to ten digit keys and a decimal point key (in white), it has total, four arithmetic function, exchange, change sign, percentage, and clear/clear entry keys (in turquoise). In addition it has a square root key and four memory keys (in orange). A mark behind the keyboard reads: Unisonic 790R. The on/off switch is to the right of this. Behind the keyboard is an eight-digit green vacuum fluorescent display.
A power jack is on the top edge.
The back of the calculator has a sticker giving calculation examples. It reads in part: 790R-C. It also reads in part: SERIAL NO. (/) 111290 (/) MADE IN JAPAN. Below this is a compartment for four AA batteries.
Compare 1986.0988.117 (Unisonic 790R-C) and 1986.0988.118 (Unisonic 790RM-C). Similar in general shape of the case are 1986.0988.116 (Unisonic 796-A), 1986.0988.115 (Unisonic 799-A), and 1986.0988.112 (Unisonic 1299R-A).
Reference:
[Advertisement], Los Angeles Times, February 23, 1977, p. I1. Unisonic 790R, a “deluxe calculator,” sells for $18.96.