After about 20 minutes while driving they jumped off my car and I lost them. The pictures show that the straps can be used to attach the toes of the tires to the car but they do nothing, they fit like a sheet over the tire and that's it. I suspected they had come loose even though they fitted the tire perfectly, and I spent a lot of time pulling as much material behind the tires as possible. I drove a few blocks, stopped and checked, then drove for 20 minutes and they came off the tires and got lost. I think the only benefit is that they didn't damage my car like the chains did when they snapped off. While I really can't recommend them, I love the concept and will probably try a different model.