So named because they "sit on top" of wide aerodynamic crossbars. These pads feature 1.5" closed cell foam. The Endura fabric covers hold up well against damaging UV rays. They are secured to the bar with full length nylon flaps with Velcro closures. Available with standard or extended flaps for extra large crossbars. Sold in pairs, packaged in poly bag with header. Logo area 14" x 1.5". Made in USA.