Formula 1 cars often produce sparks when they are racing. The sparks come from titanium skid blocks that are embedded within the plank underneath the car. The plank is made of a wooden material called Jabroc and runs from the rear of the car up to just before the front wheels. The skid blocks protrude out from the plank by no more than 3mm and exist to prevent the plank from getting damaged when the car "bottoms out". When the car hits the ground, the skid blocks hit the ground first, creating a shower of sparks behind the car in the process. The skid blocks are a legality requirement and are checked for thickness in scrutineering following qualifying and race sessions. If the plank shows wear of more than 1mm, the driver of that car will be disqualified. The sparks are not a sign of damage but rather intended to prevent damage to the car.