To maximize performance, Pinewood Derby cars should be weighted to the maximum weight allowed. PineCar #P379 Stick-On Designer Weights are easy to use - just attach to the side of your racer with the included double-sided tape. Weights can be cut with a razor saw or hacksaw to fine tune your car's weight. Package contains 2 weights of approximately 1 ounce (28.3 grams) each. Choking hazard - not for children 3 or younger.