View this product description in Norwegian.

HEXRACKII clamps get a rock solid grip on the rails with a synthetic sleeve that fits between the clamp and the rail. As the clamp tightens, it compresses the sleeve to establish a solid grip. This gives the clamp a secure, slip-free hold on the rail when tightened, and allows easy adjustment when loosened, making the whole setup process quick, easy, flexible, and solid.

The cross clamp is used to connect two hexagonal tubes at 90-degree angles (for example, to connect a leg tube with a tube that has been horizontally set).