ADJUSTABLE WINDOW GAP SIZE: With the SAFELON Window Restrictor, you can choose from two different window opening sizes: 3.62" (9.2cm) and 5.31" (13.5cm). The adjustable window slit size can meet daily ventilation requirements and more customers' needs. Material: The window lock is made of polyamide material, which is strong and durable. It helps prevent children from playing with windows or getting fingers pinched, and also helps prevent children from falling from windows. Suitable not only for babies but also for pets. Easy Lock and Unlock: Press the double button to unlock, allowing the window to be opened or closed freely. The lock design includes no keys or small parts that can be lost. Adjust the window gap by pressing and holding the slider button on the rod and pushing or pulling the window. Easy for adults to operate, but difficult for babies to manipulate. EASY INSTALLATION AND TIPS: SAFELON window stoppers include both tape and screws to assist with installation.