Update:
I have installed the aforementioned rear seat cover and am pleased thus far (dog seems to be good with it, too).

Some observations:
1. The slots for the seat belts to come through the cover are too high for my vehicle to be usable. Not a problem in my situation as the dog is the only one who rides in the back of my car. On the other hand, I have a harness for the dog that snaps into any rear seat belt and that is still usable because I can thread it through one of the cover's slots.

2. My vehicle does not have rear seat headrests. This is not a problem because I pleasantly discovered that the two adjustable (brilliant!) loops at the top of the cover will slip behind each corner of the rear seat back and thus stay situated.

3. The elastic loops at the bottom corners of the cover also fit around the corners of the bottom seat cushion (which is attached to the floor of the vehicle).

The cover seems to keep the dog from sliding around and that is a nice benefit also. So far, the cover seems to stay in place. It has two approximately 4" long PVC-type tubes that are secured to the back of the cover at around the same location as the slots for the seat belts. These are meant to be pushed between the rear seat's back and bottom cushion to keep the cover in place. So far, I have had no need to use them.

Only downside (in my view): Product is made in (surprise!) China.

All around, seems to be a very good product that does what it promises.