Pretty much its a scale. Place the car on it, there is a pin that will tell how much force the shoe is applying on the pin. Can be grams or even grains. They have been around for a while and as always I'm late to the party. I will put you touch with the manufacturer. PM me if interested. This tool is a must have pit item. Its 60 bucks but has a worth at much more. Your looking to buy your fastest car? Its already in your box you just don't know it yet, now you do.