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 while 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), exceeding the industry standard of 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 household and acts as a burglar deterrent. 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 while keeping pets inside or outside the house. The child lock can be unlocked to allow access to the window in case of emergencies. APPLICATIONS: This door restrictor can be used on all types of windows and doors including UPVC, aluminum, wooden, and metal profiles. The child window safety locks can also be used on fire escape windows as long as the keys are within easy reach. EASY INSTALLATION: These window safety restrictors are surface fixed, making them easy to install and suitable for anyone to fit. The XFORT window locks for UPVC windows come supplied with all necessary fixtures and fittings such as screws and a key.