I bought a couple mate, then I bought more and put one on every tow bar.
https://www.youtube.com/watch?time_c...&v=62bmgwwRpyo
Less high tech than a camera but gets the job done. Oddly I always manage to get the AU ute bang on, but for some reason have a devils time getting the el sedan or the forester aligned, so the cm has saved the plastic bumpers on those 2.