This is probably one of if not the best add on back-up cameras available.
Alpine Electronics of America, Inc.
I am running this one with my KEnwood HU and I also have the Nissan in rear-view mirror monitor and back-up camera too. I have videos of both in my journal. The Alpine gives you 4 selectable views with its camera and also audio and visual warnings when objects are behind your car in blind spots. It works great.