Sturdy Material: Our roof box bracket made of premium galvanized steel and plastic is sturdy, wear-resistant, and durable. The roof box bolts are not easy to break or deform and have a long service life. Package Contents: Universal Car and Van Mounting Kit: This roof box accessory kit contains 4 galvanized steel U-bolts, 4 rubber washers, 4 plastic support plates, 8 high-performance security nuts, 2 bandages, 1 door step pedal, and a dot sticker to meet your different needs. Good Compatibility: Our universal roof box car van mounting fitting kit is suitable for most vehicles on the market. Inner width: 85 mm, center-to-center thread width: 90 mm. The screws have a diameter of 7 mm. Can be used with roof bars up to 40 mm thick. Easy to install: The universal roof box clamps are small, lightweight, and take up little space, making them easy to store in the room or car. It is easy and convenient to install and easy to use.