- It is made of thick iron material, which has strong pressure resistance and durability. 2. Rotate the screw to tighten the switch and snap it into the window slot. 3. Rotate the switch to change the distance between the slots at any time. (The slot distance between the two moving windows should not be greater than 4cm, nor can it be less than 2.5cm, so as not to affect the stability of the safety lock)