Weights are one of the most important factors when building a winning derby racer. The heavier your racer is, the faster it will go! Most racing specifications require your racer weigh as close to five ounces as you can get it, but must not exceed five ounces. These weights are incremental, which allow adjustments to a car's weight, even on race day! Break off just enough to meet specifications, keeping the car as heavy as possible. Attach the weight to bottom of the racer, or counter-sink it under the car with the screws that are included. Total weight approximately 1 ounce.