Essentially a ZX81 with NTSC circuitry and the usual channel selector switch poking thru a hole in the bottom, memory was also *doubled* to <gasp> 2K! Timex later redesigned the board, and also produced a 16K version in a Spectrum-like case called the 1500. (Why not 1600?)
The machine retailed at $99.

I've been told it's possible to change an NTSC machine back into a PAL one by simply snipping a jumper wire, but I'm not about to find out for myself :) This particular machine has travelled from the US to the UK via Australia - it's endured enough! And I think it doesn't work :(

*Update* 15/01/02. Decided to open up my little world traveller to see what made her tick, expecting to see a ZX81 board with a couple of mods. What I *wasn't* expecting to see was a redesigned board in a fully sprayed and shielded case; click on the thumbnails to see what I mean, and compare with the ZX81 kit page for board layout! Note in the last one (if it's visible) that it's still possible to put a UK modulator in there and get a PAL signal......