Features: 1. The roof box accessories are made of high-quality stainless steel, rubber and reusable plastic, wear-resistant, corrosion-resistant, not easy to break and deform, and durable. 2. Internal width 85mm, width from the center to center of screw threads 90mm, the bolts are 7mm in diameter. Can be used on roof rack rail up to 40mm thick. 3. The roof box u bolts are equipped with rubber gaskets and plastic back plates, which can protect your car from scratches to the greatest extent, and can increase friction to improve overall stability. 4. Easy to install, use the attached accessories to assemble, the installation is stable, simple and convenient. 5. Easy to carry and store. The auto parts are light in weight, occupy a small space, and are easy to store in a room or in a car. Notice: 1.Actual color may be slightly different from the image due to different monitor and light effect 2.Please allow 1-3cm deviation due to manual measurement : Material: Stainless steel + Rubber + reusable plastic Size: Internal width 85mm Width from the center to center of screw threads 90mm The bolts are 7mm in diameter Can be used on roof rack rail up to 40mm thick Product weight: 800g Color: Black Package: 8 screws, 4pcs/ each x other tool ( U-Bolts etc) includes: 1 set x Car Van Mounting Fitting Kit