- Size Specifications : Each bolt has a diameter of 7.5mm (0.3 inches). The internal width measures 83mm (3.27 inches) with a center-to-center screw width of 90mm (3.54 inches), ensuring compatibility with a variety of roof racks and cargo systems. - Complete Package : The set includes 4 iron U-bolts, 4 rubber washers, 4 plastic backing boards, 8 lock nuts, and 2 bandages, providing everything you need for a secure installation. - Enhanced Durability : Designed to withstand deformation, these roof rack mount U-bolt clamps feature a rubber gasket and plastic back plate to minimize scratches on your vehicle while enhancing friction. This ensures strong confinement and a remarkable bearing capacity. - High-Quality Material : Constructed from galvanized steel, these U-bolt clamps are resistant to alkali and corrosion. The clear thread design ensures a snug fit and uniform pressure distribution, improving overall stability and minimizing slippage. - Versatile Applications : Ideal for securing cargo boxes, ladders, and bicycle racks, these U-bolt clamps provide peace of mind during transport. Whether for family road trips or outdoor adventures, they are engineered to safely accommodate added weight without compromising vehicle integrity. - Easy Installation : With a straightforward setup and all necessary components included, you can quickly secure items to your roof rack, making loading and unloading hassle-free. With these U-bolt clamps, ensure your gear is protected and securely fastened, making them an essential addition to your vehicle accessories.