We had some yellow plastic chocks for our trailer but one day we hitched up a trailer to drive away, pulled it out and went right over the wedge without realizing it. We figured if the chock does what it's supposed to do, at least you should feel like something's wrong when trying to ride it! These wheel chocks are a real thing - heavy and big enough to keep the trailer from rolling. They're built the same as those used on commercial trucks and should last forever. Good value for money. Shipping something this heavy could have ruined a deal, but with Prime it was the way to go.