[KC8ZKF]

It was sold as the Timex Sinclair in the USA.

I was planning on buying one, but ended up with a used VIC-20 instead.

[sys_64738]

Commodore USA had a trade in offer that you got 100$ off the cost of a C64 if you bought a new C64 and traded in the ZX81. You could pick up ZX81s for 50 bucks at the time. Meanwhile Commodore was flooded with ZX81s that they didn't know what to do with. Then the C128 came along and the needed Z80 chips. The rest is history.

[Someone]

The Timex Sinclair was a variation on the ZX81, not a Spectrum.

[UncleSlacky]

The Timex Sinclair 2068 was the US Spectrum variant:

https://en.wikipedia.org/wiki/Timex_Sinclair_2068