Weights are one of the most important factors when building a winning derby racer. The heavier your racer is, the faster it will go! These weights are incremental and scored so sections may be broken off, even on race day. Most racing specifications require your racer weigh as close to five ounces as you can get it, but must not exceed five ounces. Round Weights are easy to install. Drill 3/8 inch diameter hole in car. Cut off the weight you need, keeping car as heavy as specifications allow. Then insert the weight into the body of the racer. Total weight approximately 1.5 ounces.