Very well made rubber wheel chocks. There is no flexibility. Stay in place. We bought two pairs to orient our cars for maximum garage space when the door is closed. We only need one per car and truck and the chocks stayed in place for months during the winter season. Literally never moved. That in itself is impressive considering that in winter they are surrounded by dirt, dust, salt and ice. Compared to the plastic pads we tested, this pad is relatively heavy and definitely made for heavy use. I see reviews about the smell with them. When they arrived and we opened them in the kitchen, there was a strong smell of new rubber, like new tires. But it was in the house and after putting them in the garage we didn't feel any smell. currently. The traction and position of these pads depends on your gender. We tested them on a smooth wooden surface and they needed the smoother side down, but on a rough concrete floor they needed the grooved side down. We also use them on our cars, trucks and tractors to keep the vehicle securely in place. We will be buying more to accommodate the cars we are storing for the winter. In short, this is exactly what we expected.