Sport Rack Kayak J Stackers attach directly to roof racks from Thule, Yakima, Whispbar, Malone and most factory installed roof racks. The economically priced J Cradles hold one kayak and include roof rack tie-down straps, bow stern tie downs and bumper hooks. Sport Rack Kayak Racks and Carriers are on sale, in stock and ready for immediate shipping from RackWarehouse.com. If you need assistance choosing the right kayak rack for your vehicle and budget, please call us at 800 272-5362. Other Sport Rack products to consider.