A spray-on bed liner is a protective coating applied to the bed of a pickup truck. It is designed to prevent damage from scratches, dents, and rust caused by heavy loads and weather exposure. The liner is typically made from polyurethane or polyurea, providing a durable and waterproof barrier. The application process involves cleaning the truck bed and then spraying the liner directly onto the surface. This creates a seamless, custom fit that adheres well to the metal. Spray-on bed liners are popular among truck owners for their ability to enhance the vehicle's longevity and maintain its resale value.