Materials: This U-Bolt is made of stainless steel. According to research, stainless steel has weak magnetism, so it will also be attracted by magnets.High Quality:Roof box fitting is made of stainless steel, which is wear-resistant, anti-oxidation, not easy to break and deform, and has a long service life.Easy to Use: Roof box brackets are small-sized, lightweight and space-saving, can be placed in the room or in the car. The installation is simple and convenient, and it is convenient to use.Universal size: Inner width: 85 mm. The width from the center to the center of the thread is 90 mm, and the diameter of the screw is 7 mm. Can be used with roof reinforcement up to 40 mm thick.Specifications:1. Suitable for luggage racks up to 40mm/1.57in thick2. Internal width: 85mm/3.35in3. bolts diameter: 7mm/0.28in4. Center to center of screw width: 90mm/3.54inStep:1. Lock the tensioner from the top or bottom;2. Insert the pipe and lock it directly with the U-bolt and crossbar;3. Input on rubber discs;4. Put on the spring washers and fasten with nuts, then you are done.Material: metalColor: BlackPackage Contents:1 luggage accessory kitsOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.