I have posted a video to show both cameras, the front will show you front/rear or picture in picture but the screen is too small for leaving that on.
It was easy to set up - just plug in the one wire that supplies connection and power to the rear cam. It records to the front! Very easy.
Good quality video - better than most rear cameras I've seen!
IF Keeken can build a fully wireless rear - just need to find power from the rear...that would be great!
The quality does not seem quite as crisp as the front but perhaps it is due to the placement during testing. I will place right up against window in perm. placement.
Overall this seems like a solid addition to the front cam. I enjoy putting good effort into these items I buy as I feel that every car should have one for safety. IF there are issues with reliability i will update this posting.
PS Sorry for the raindrops on my car windows!