What is the difference between roof rails and flush rails?

The primary difference between roof rails and flush rails lies in their design and appearance. Roof rails are raised structures that extend above the roofline of the vehicle. They often provide a more rugged or utilitarian look and can serve as attachment points for various accessories. Flush rails, on the other hand, are integrated into the vehicle's design, lying nearly flush with the roof. Flush rails offer a more streamlined and modern aesthetic.