With a set of Yakima Hully Rollers on the back of your cars roof rack, you can easily position your kayak on your car top, even by yourself. When the boat is in place, strap it down securely right to the Hully Rollers. (You'll necessity either a second set of Hully Rollers, or other saddle mounts such as the Mako Saddles (sold separately) to Strength the front of the boat.)Pivoting rollers smoothly slide the kayak on and off the vehicle's top. The U-shaped rollers fit any boat shape. Rollers lock in place and do not roll when locked during transport. The rollers are padded with Dynaflex, a soft, durable composite material, for sure grip on your boat and long wear. Attach easily to crossbars. For factory racks use Yakima Mighty Mounts (sold separately). Includes 16' Yakima padded Heavy Duty Strap and Bow/Stern Tie Downs.