When we turned our baby's car seat around to the front-facing position, we lost the ability to see her easily in out rear view mirror. I couldn't position the mirror to safely see the traffic behind me and my little girl, so I had to raise myself up just to be able to see her face. I just happened to find this at Walmart one day so I gave it a try.
This little mirror looks just like a regular rear view mirror, just smaller. It attaches to the back of the car's rear view mirror by a sticky pad. I tried to readjust it about 4 times in different places and the sticky pad didn't get any less sticky. The mirror is long enough that I can see both sides of my backseat. This will be great for when we have another baby in the back on the other side. The mirror is decent enough to see my little girl well. It seems to make things appear smaller than they really are, but I can see her with good detail still.
The mirror is adjustable side to side and back and forth. This is great because I can turn it and see her when I am in the passenger seat too. It can fold back behind the rear view mirror when you're not using it too. It's a good idea to do this because the mirror does give you a blind sight right in the middle of your windshield.