Helps prevent children from opening the window beyond a safe distance, reducing the risks of falls. This latch is great for all windows. They can be used on aluminum, wood, or plastic frames and is suitable for sliding, sash, and outward/inward opening windows accommodating most homes. Allows you to open the window and enjoy the weather while knowing children are safe. The locking mechanism is simple, just insert the cable head and slide it into the locked position. When it’s time to clean the windows, it can be easily disengaged by an adult. Limits the window opening to 4 inches (10cm) at its widest point. The easy to follow instructions are included.