Ventilation Adjustment---Our window restrictors are adjustable and can protect children while meeting the function of ventilation. There are two different opening sizes to choose from, 3.62" (9.2cm) and 5.31"(13.5cm). Press and hold the slider button on the pole to push or pull the window, achieving the adjustment of the openging size for windows. Why you need it - Prevents babies from getting their hands caught when opening and closing windows without adult supervision; prevents babies from climbing on windows; prevents toddlers from accidentally falling out of windows. It is effective not only for babies, but also for pets. Universal and Durable --- Made of PA66 + GF20 material, the window openers are strong and durable with two parts. Our window locks can be used for windows that open both inward and outward. Installation Tips --- Screws and 3M VHB Clear Adhesive are combined to achieve the best installation effect. 3M VHB transparent adhesive has super adhesion (the effect is better after 24 hours). ) and can be easily removed without leaving a trace. Easy to use: the window openers can be easily unlocked without the need for a key. Press the two buttons on the lock body and push the window to unlock it, so that the window can be opened fully as usual. Easy to use for adults but difficult for babies to open, providing effective protection for babies.