Double Lock Design & Easy Installation: 2024 Newest upgrade protection design, each window lock with two fixing holes that greatly enhance the holding power of the lock. You can easily secure your window/door or allow ventilation by tightening the lock clockwise with the included hex wrench. Please refer to the fourth installation diagram before installing.Special Rubber Protection Pads: To prevent lock scratching or damage to the window, window lock clamps specially adds a rubber pad layer that enhances the friction between the window track and lock, to improved stability and security. At the same time, we are also equipped with a vertical key, you can easily install the window lock to the inner rail of the window, which can solve the risk of children or thieves opening the window.Package Includes: You will receive 4 sliding window locks, 4 hex keys, 1 vertical hex key, 4 rubber protection pads. Our window locks provide increased security for sliding doors/windows. If you have any questions or concerns, please contact us. We will reply within 24 hours.High-quality Safety Window Lock: The window stopper is made of hard aluminum alloy that is rust-resistant, waterproof, and anti-aging. It can effectively prevent the risk of children and pets falling from heights, protect your property during storms, and prevent theft or property damage during your outings. Our childproof window locks for your home, office, children's room, kindergarten, or elementary school.Measure Your Window Track Size: To ensure a perfect fit for your window, please make sure your window track height is greater than 0.7in (1.9cm) and width is less than 0.67in (1.7cm). Our window restrictor works with horizontal windows, horizontal doors, and vertical windows.