Adjustable Window Gap Size---With the window limiter, two different window opening sizes can be chosen, 3.62"""(9.2cm) and 5.31"""(13.5cm). The adjustable window gap size can meet the daily ventilation requirements and needs of more customers. Why is it necessary---The window lock is strong enough because it is made of polyamide. Don't hesitate, it can prevent children from playing on the windows and pinching their fingers, prevent children from falling out of the windows, etc. Not only for babies but also for pets. Easy Lock and Unlock---Press the double button to unlock the lock and the window can be opened or closed freely. No key or other parts missing with the lock installed. Adjust the window gap by pressing and holding the sliding button on the pole and pushing or pulling the window. Easy for adults to use but difficult for babies. Easy to Install & Tips---The window restrictor provides tapes and screws for customers to install. With the tapes, it can bear less than 58 LBS (the effect will be better after 24 hours). Please select the appropriate installation method based on the actual requirements. Wide Range of Applications---Used for inward opening windows and outward opening windows. Suitable for most windows on the market.