Roof Rack Pads (Sit on Top) for SUP or Surfboard - Aero Style - 2pc Set (30 Inch) Made in USA using high quality materials, built to last. Heavy duty and durable polyester fabric provides a much needed layer of protection between the board or kayak and the crossbars. The unique solution dyed polyster helps preventing cracking, chipping, peeling and flaking from the elements (such as extended exposure to the sun and salt water). The core of the pad is constructed from closed cell foam (one and a half inches thick), a material designed to increase structural strength, water vapor resistance, and UV protection. Sit on top of wide, flat crossbars (Aero only - typical size 2.75" x .75") commonly installed on SUVs, vans and trucks. Full length velcro closure secures pads to flat aerodynamic rack crossbars. Best for SUP, surfboard and even kayak transportation to and from lakes, rivers and the ocean.