About This Item 85mm Inner Width: Our roof box kit fits most vehicles on the market. The center to center width of the screw thread is 90mm. The screws diameter is 8mm. Premium Material: Made of galvanized steel and high quality plastic, our roof box u-clamps are durable, strong and have a long life. service life. Safe Design: With user-friendly rubber seal and plastic back panel design, which can protect your car from scratches and keep your luggage safe. Easy to Use: Our roof box kit is convenient to install, lightweight, small in size, and can be easily stored in the room or car. Complete set: Our roof box kit contains 4 stainless steel U-bolts, 4 rubber washers, 4 plastic backing plates, 8 lock nuts and 2 fabric bandages