This is a large piece of rubber used to prevent the vehicle from rolling backwards. I bought it for safety when handling vehicles on jacks or ramps and in case I need to park on a steep hill for an extra level of security. I had no reason to give it less than 5 stars, but I didn't rate it after multiple uses or multiple freeze/thaw cycles in my truck's tool box. Seems to be a solid product. The eyebolt for attaching the chain reminds me of the ones that stood under our cars in the Bundeswehr. Not sure if it's very useful, but a nice addition. If you need something to keep your light or medium truck from rolling back, this will do.