Quite happy with it in theory. Set it up in about 20 minutes; This requires some guesswork, checking and adjusting the nut, which isn't the easiest to use, but simple enough. Added a lock and everything seems safe. I'm reducing my rating because the instructions say not to rely on it and to use alternative chocks as well. I'm not sure if it's just a CYA legal thing or if they aren't safe on their own, but I would just buy something else if I knew it wasn't enough.