Adjustable Window Gap Size --- With the window restrictor, 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 It Is Necessary --- The window lock is strong enough because it is made of polyamide. Don't hesitate, it can prevent children from playing at 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 & 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