Three clamp bracket sizes included for different factory rail widths. These adjustable feet clamp onto the factory roof rails from 20mm (0.8'') to 45mm (1.8'') wide by using the appropriate clamp size. Made of 3CR12 stainless steel and sealed with the same durable, weather resistant black powder coating as the Front Runner Slimline II Roof Racks. Rubber padding creates a protective layer between the clamping foot and factory roof rail. Includes all necessary installation hardware and fitting instructions. No drilling or vehicle modification is required. NOTE: Not suitable for Flush mount factory rails.