You’d turn it on, the display would blur, then when you hit the freeze button it would stop on the last two digit number. It was harder to use than a pair of icoscahedal dice but it was much cooler.

I got the circuits from the Radio Shack blue book of electronic projects. The chips were mounted on a strip of perf board and wire wrapped (which is so much easier than the old stick-and-solder method). The board was mounted on a black box with the battery and switches, components out so it looked all high-tech and electronic.