I ordered the mini-keyboard at the top of this thread, and I received it today.
It works as advertised.
I measured it at 6 5/8" X 2 7/8". (Not counting the USB cable.)
It has a couple sticky rubber strips on the bottom that keep it from sliding around.
The bottom is also contoured, making it easy to hold in both hands for thumb typing.
It's too small for my adult male hands to type, but to occasionally adjust settings it's fine.
I do find it very difficult to read the blue markings that give each key's value when the "Fn" key is pressed.
- Mark