The system is easy to install and consists of an external adaptor and oval shaped blades, which are fixed to the outside of an inward opening window, and can be positioned horizontally or at any angle up to 45 degrees in either direction. This means the windows can open to their maximum angle, maximising ventilation whilst guarding those inside from the risk of falling from the window. The Louvre Guard System is either fixed through the face of the window or through a bespoke coupling mullion therefore maintaining the thermal barrier.