Just a User Report on my WalMart carpet mats or runners.
Some time back, I purchased two mats or runners that have a black backside, kinda like a rough-finish automotive undercoating. Many small, sharp points stick out and grip the carpet of my Egg, almost like Velcro. I am happy with these mats, as they have moved forward only a minimal bit and when I pick them up, I can hear them "ripping" a little bit, like Velcro.
On the top side, they have molded "grooves" running the long way. My color is basically dark green with a bunch of other-colored threads running thru it.
The backing is essentially water-proof, so if I spill anything on it, I can clean it up without wetting the Egg carpet (unless it runs off to the side in a groove).
Pete and Rats