We bought these for use with our pop-up camper and they work very well for that purpose. They are toothed on top and bottom to allow for good traction on most surfaces and the curve of the top fits our tires quite well. These are lightweight and have holes for use with a rope if you prefer to tie them together. While they are not as rugged as rubber chocks, they work very well for our purposes and I will likely replace them when they get old or worn.