S.D.
I measured my moby wrap and here's what I got:
16 ft long
21 inches wide at widest
4" at the very narrowest end
I folded it in half, and it's at 21" width for 70" before tapering it down (so 140" unfolded).
Tapering is just gradually narrowed down and it's rounded at the narrow ends. Hope that makes sense.
Mine is 95% cotton with 5% spandex. This is an awesome blend if you are trying to make your own because it give support with a little bit of stretch and it also makes it breathe well so you aren't sweating. Of course it is also a knit.