A bed liner is a protective coating applied to the cargo area of a pickup truck. It helps prevent damage from scratches, dents, and rust caused by transporting heavy or sharp objects. Bed liners can be made from various materials, including rubber, plastic, or spray-on polyurethane. There are two main types of bed liners: drop-in and spray-on. Drop-in bed liners are pre-formed plastic liners that fit into the truck bed, while spray-on bed liners are applied directly to the surface, creating a seamless and durable finish. Both options enhance the longevity of the truck bed and maintain its appearance.