A security shutter is a roller shutter designed to resist being lifted or forced from outside. It usually combines stronger slats, in extruded aluminium or steel, with some system that stops it from being raised.
What makes it secure is not just the material. What counts is how it is held at the bottom, whether the bottom slat can be bent and whether it can be pulled out of the guide rails.
There are two ways to go. One is to replace the whole shutter with one built to resist more, which is a bigger job. The other is to reinforce the one you already have. That is our work: we reinforce shutters so they cannot be lifted or bent, with a 4 mm steel T-profile on the bottom slat and bolts that lock into the wall.