WHAT YOU GET 4 sets of window locks for sliding windows, including 4 sliding window locks stopper, 4 keys and 4 gaskets, can fully meet big family/large house requirement. Note: Heavy doors and windows should be fixed with multiple locks at the same time to improve stability and safety. WINDOW LOCKS SECURITY Size approx. 1.18 x 0.94 x 0.94 inch, apply to track with more than 0.6 inch heights and less than 0.63 inch thickness. Effectively reduce the risk of children pets falling from heights, guard against theft. Keep your house safe, limit and fix windows for ventilation to improve indoor air quality. PROTECTIVE GASKETS Each sliding window locks also comes with a plastic protective gasket to prevent scratches or damage to the window. This locks for windows with protective gasket can provides enough friction between the lock and the track to ensure that the window will not slide open. UPGRADE PROTECTION DESIGN This window lock is made of solid aluminum alloy, anti-rust and anti-aging. The upgraded vertical window locks design allows the key to be removed and stored properly to prevent toddlers from opening it by mistake. One more layer of protection to eliminate all potential hidden dangers. EASY TO INSTALL This adjustable lock for home is suitable for both windows and sliding doors. All you need to do is to spin the key through the hole and fix the window stopper on the track. No additional installation tools are needed. Please note that this window lock with key does not fit the middle track of the window.