FUNCTION: These window safety locks enable you to restrict the opening of a window to under 100mm for safety and security reasons. One unit of the UPVC window restrictor is applied to the frame or mullion of the window whilst the second is attached to moving window allowing for controlled opening. QUALITY: XFORT window restrictors for upvc have been designed to withstand forces of over 1000N (100kg) despite the industry standard of only 50kg. The locking system and key are both oxidation and corrosion resistant to prevent damage or wear and tear. SECURITY: This window lock protects your family and acts as a burglar deterrant. The limited opening of the window can prevent a child from fitting or falling through the gap. It can also be used to circulate air without allowing pets in or out of the house. The child lock can be unlocked allowing for access to window in case of emergencies. APPLICATIONS: This door restrictor can be used on all types of windows and doors including UPVC, aluminium, wooden and metal profiles. The child window safety locks also be used on fire escape windows as long as the keys are in easy reach. EASY INSTALLATION: These window safety restrictors are surface fixed so they are easy to install and can be done by any one.The XFORT window locks for upvc windows come supplied with all fixtures and fittings such as screws and a key.