Metal wheel chock are stronger and not easy to be destroyed when pressed by wheels.

--Wheel chocks are a relatively cheap investment in your safety and the safety of others. To prevent the cars or trailers or trucks or other vehicles from sliding when they are on a slope.

--Anyone who has shopped for wheel chocks knows there are a variety of options available on the market. 

Wheel chocks are manufactured in different shapes and out of different materials. All, however, are inclined planes and if used correctly, each should perform the job. Since all wheel chocks provide a hill for a wheel to climb if it wants to roll, it doesn't matter if it's two inches or two yards high. That lack of difference pertains only to a perfect wheel, though, and tires aren't perfect wheels. They can change their shape. Tires aren't rigid, so a tire can bend around a small enough chock and continue on its roll downhill.

--In the case of selecting a wheel chock for tires, the bigger the better. Many wheel chock manufacturers also specify what tire height their chocks are designed to accommodate.

--Both metal and synthetic materials are often used for wheel chocks.

--Rubber wheel chocks provide stability through the friction created between the non-slip material and the ground.

--Polyurethane wheel chocks are more stronger than rubber wheel chocks in same weight and size, because of the material difference. And the use life of polyurethane wheel chocks are longer.