B00005AXI6

Park-Zone is an innovative precision-parking device for the home that's easy to use and even easier to install. After a simple one-time setup, the Park-Zone uses its ultrasonic sensing mechanism to measure the distance from your car to the garage wall as you park. When you pull into the garage, you see the green light illuminate, then midway it changes to yellow, and when the light turns red you're right where you want to be. In our book, this beats a tennis ball hanging on a string because it's a lot easier to set up, it's much more precise, and, unlike the tennis ball, it looks good in a garage. Anyone who parks in a small or crowded garage will appreciate the accuracy this gadget offers. The Park-Zone operates on four AA batteries batteries. Stop bumping the back wall and get into the Park-Zone. --Brian Trinen