It was a member of a line of computers created by Sinclair Research in England. They teamed up with Timex to market them in the US. Odd, interesting, low cost design. You would use your TV for a low-res monitor and a regular cassette recorded for a tape drive. I had the ZX81 way back in '81.
More info here:
http://en.wikipedia.org/wiki/Timex_Sinclair_2068