With a built-in RES™ rail expansion system, UltraGroove™ makes it easy to attach nearly any Thule® or Yakima® rack for bikes, kayaks, cargo baskets and more. With or without racks, it's incredibly easy to use and it's covered with a weather-resistant, padded ArmorTek deck laminated to rigid aluminum panels. It opens quickly with just a turn of the lock knob and closes just as easily with a pull on the built-in strap.