Skid block

Skid block of the Honda RC-F1 2.0X test car.

A skid block is a common term for a mandatory attachment to the underside of a racing car. Initially applied to Formula One cars in 1994, it has also been used in other categories including Formula 3000 and Formula 3. It is a flat rectangle, usually made of fiberglass or a wood composite, designed to impose a minimum ground clearance and to limit the use of ground effects to enhance handling.