This is our second one of this type. The first one was over 10 years old and was broken. Just replaced it. Don’t have to use batteries. You can easily see it move when you bump it. Helps us park truck in detached a garage that is a tight fit.It only detects when my bumper hits it, but at least I am no longer bumping my garage shelves!So simple and practical. Sets up in less than a minute. Very sturdy weighted base to keep in place. Sensitivity is perfectly set.I already bought and setup a second unit for our 2 car garage. It is just as good as the first one. That indicates consistent high quality for this product.I wholeheartedly recommend it to safely park your garaged car(s).Does the job it was designed to do. Especially at night when it’s dark. It makes parking a lot easier day or night. Design and construction are adequate. Yes it develops a slight lean, but who cares? It’s a handy gadget to have around. Beats a hanging tennis ball or bricks on the floor. Plus my grandson loves watching the “light show” when I park the car.The light doesn't always flash but it's still usable. It's set up that when the bumper hits it, it tilts and that let's me know that's the limit. Still using it!Great product and easy assembly. I did have a major problem with the delivery. Either FedEx or UPS delivered my order to the local post office. The postal service held it for reasons only known to them. I leaned on them pretty hard and it was found and given to me with some really incredible excuses.Works as it should. Just worried about the sturdiness of it.You drive in til you bump it and it says to stop and lights up. Thus, knowing you have reached the spot.