The Thule 554XT Hang Two Rooftop Surfboard Carrier is an upgraded version of the popular Hang Two carrier, with factory rack compatibility, and improved board protection. The 554XT can simultaneously carry up to two surfboards right out of the box, no longer requiring the Thule 504 Surf Strap to transport the second board like the old Hang Two units. This surfboard carrier provides you with maximum surfboard protection and lateral transport stability via the soft, oversized cradles, while strong, easy-to-use straps provide additional board protection, as well as transport security. The 554XT comes with universal mounting hardware that adapts easily to Thule square and Xsporter load bars, as well as Yakima, and most factory-installed racks. What's in the Box? 2 x 554XT rooftop carrier bars, 4 x bases, 2 x attachment straps, 8 x carriage bolts (M6), 4 x metal brackets, 8 x 3-wing knobs, and instruction guide Manufacturer's Warranty Limited lifetime warranty