LINE-X SPRAY-ON TRUCK BEDLINERS AND MORE! LINE-X is the industry leader in truck bed protection offering specially formulated polymers that permanently bond to your truck's bed protecting it from just about anything you or Mother Nature can dish out. And LINE-X protects more than just trucks. What LINE-X can do for truck beds, it can do for truck covers, rocker panels, fenders, bumpers, etc. As one of the nation's leading providers of spray-on protective coatings our products are utilized in commercial, industrial, agricultural, military and custom applications.