If you have a Rhino-Rack Heavy Duty Crossbar system or a Prorack Trade Crossbar and would like to mount Rhino-Rack's range of Kayak and Canoe Carriers including the Nautic 570 and Nautic 571, you will require the HD-FK1 fitting kit. This kit contains bolts and washers only. The kit comes with all the necessary bolts and washers to attach the kayak carriers to your Rhino-Rack Heavy Duty Bars or Prorack trade crossbars. Features: Attach the Nautic 570 and 571 Kayak and Canoe Carriers to your Rhino-Rack Heavy Duty Bar Attach the 562, 564, 566 to your Heavy Duty Bar Comes with bolts and washers only