Hammerglass Add-On is a complete integrated system of effective burglar protection designed for external or internal installation over existing windows. Hammerglass Add-On can be fitted to fixed or openable windows as well as to glass- and door sections. The Add-On profile protects and reinforces existing wooden frames, and this in turn reduces maintenance costs to a minimum. The system also provides energy savings and improvements in the U-value, as well as a noise reduction of 30 dBRw. Hammerglass Add-On is recommended by insurance companies as an alternative to anti-theft grilles and roller shutters.