skid plate

A skid plate is an abrasion-resistant shield affixed to the underside of a vehicle or boat to prevent damage to the underside when contact is made with the ground. It is usually made from plastic or metal (usually aluminum or steel).
Skid plates may be used on off-road vehicles, motorcycles and lowered vehicles to prevent damage to components in the vehicle underbody. Fake skid plates are also added to vehicles for an off-road look.

View More On Wikipedia.org