This is a matched pair of fully-functioning Yakima Raptor Aero bike racks (previous version of the model, but still great), mounted on an included rack (or they can be mounted on your own roof rack). They secure onto the front down tubes of the frames of your bikes, and each has both its ratcheting straps to secure the wheels. They are adjustable in every conceivable way, and will fit virtually any bike. The locking frame clamps, themselves, are adjustable to fit a wide variety of frame widths, and they're lockable (locks work great, and the key is included) to ensure your bikes stay on the roof when you leave them there. New, the pair would cost just under $500, not including the rack. Asking only $175, for quick sale.