Highly recommended replacement for the tennis ball on a string...
So far, everything about this is great. Set up took all of 30 seconds. You choose the height. It comes with four 12-inch segments. I suppose you could use 2 if you have a sports car or all 4 if you have an SUV. For my car I only used 3. It works fantastic. In fact, it's almost too sensitive. My only concern at this point is how long the little button cell batteries will last. The lights are LED, so the batteries should last a while as should the light bulbs themselves. While the LEDs are not replaceable, the batteries are. You can find these at many places costing anywhere from $20-$35. I got mine for $20 @ Bed Bath & Beyond before Xmas and was able to use one of their many 20% off coupons, so shop around.