When mounting Master Fit Roof Boxes to the Rhino-Rack Heavy Duty cross bars, you will need a RUBK-MF Fitting Kit. This is a set of 4 square u bolts designed to attach the Master Fit Luggage Box directly to the Heavy Duty Style Cross Bars.• Fits the Rhino-Rack Roof Box range to the Rhino-Rack Heavy Duty style cross bars
• Easy to install
• Powder Coated Steel plates that resist corrosion