EASY TO INSTALL,BUT I FOUND OUT THAT IF YOU UNPLUG IT THAT YOU HAVE TO RESET THE DISTANCE TO THE CAR,SO I WAS WONDERING IF THE POWER GOES OFF AND YOU DON'T KNOW IT, WELL, THE RED LIGHT WILL NOT COME ON UNTIL IN MY CASE , YOU WILL BE TOO CLOSE AND BAM GOES THE WALL. I THOUGHT THE BATTERIES WOULD BE A BACK-UP WHEN THE POWER GOES OFF BUT IT SAYS NOT TO LEAVE THE BATTERIES IN IF YOU PLUG IT IN. ON THE GOOD SIDE IT WORKS VERY WELL WHEN THE POWER IS ON  BILL