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 Need It---Prevent babies from pinching their hands by opening and closing windows without the supervision of adults; prevent babies from climbing on windows; prevent toddlers from accidentally falling out of windows. It is effective not only for babies, but also for pets. Universal Durable--- Made of PA66+GF20 material, window restrictors are strong and durable with two parts. Our window locks have a wide range of application, and can be used for inside opening windows and outside opening windows. Installation Tips---The screws and transparent 3M VHB adhesive are combined to achieve the best installation effect. Transparent 3M VHB adhesive has super stickiness (the effect is better after 24 hours.), and can be easily removed without any residue.