The window lock prevents children from falling when the window is open. It can be used only on sliding doors. Clean the area before installation; place it on the top of the window. Refer to Fig. A (OPEN-less than 15cm). Remove the tape on the back of L shape; and attach it to panel on the left; slide it to the right; attach to the frame of the right panel. Hook the sucking part onto the groove of the L shape t to complete the installation. To close the window simply releases the hook.