|Weights are the closest thing to an engine that you can put into your Pinewood Derby TM car. Tungsten is the best all-around weight. Its unique high density allows the best control of the center of mass of the vehicle. Manufactured to exceedingly tight specifications, we are not talking about your uncle's fishing sinkers here!
Sized for a hole drilled by a 3/8-inch bit. They are 7/16-inches tall and weigh 0.5 oz each.