The flexible rubber flare mounts from underneath the wheel arch, it can be attached using tech screws or bolts.

To obtain a more rigid and flatter shape just insert 4mm wire through the hole in the outer edge of the rubber. The wire can be bent to help maintain the wheel arch shape.

Using the wire technique as above the flare will add an extra 70mm in width to your guard. 

Being flexible it does not break.

Rubber Flare