If you need to stop your mouse cable from falling into the back of the desk and give you hard time moving the mouse, then you can use this baby. Just put these two parts around your cable and glue the bottom of it to your desk.
The mechanism works as; these parts don't naturally fit into each other because their dimensions don't fit. In order to fit, the larger one needs to be bend outward, while the smaller one needs to be compressed inward. Because of the angles of the walls, squees force between them will push the small part down, and this way, it will squeeze the cable between the two parts.
So, to be short, you will squeeze your cable without using a screw or a nut.