What kind of computers/laptops support the new orientation features of Firefox 3.6?

What kind of computers/laptops support the new orientation features of Firefox 3.6?

I just downloaded Firefox 3.6 today and I noticed in the list of new features they have an Orientation API that can detect the direction that your laptop/computer is tilted. This is clearly a hardware feature of some sort, and I was just wondering if anybody knew a list of computers that would support such things.