SportRack ABR511 J-Stacker Kayak Carrier Car-top kayak carrier has J-style hooks that create more room while keeping your boats secure when you're on the move No adjustment needed; simply lift your boat onto the roof, tie it down, and go Mounts to most factory and aftermarket crossbars up to 3.5 inches in diameter via included universal mounting hardware Included heavy-duty tie-down straps with cam buckles and galvanized steel bumper hooks further secure your kayaks Impressive combination of design, durability, and affordability