Insect screens are held to the window frame using magnets, 1 magnetic strip on insect screen & another pasted on window frame with adhesive tape . The attracting magnets forms a seal around the window frame and also allows you to easily open / close your windows or remove the whole insect screen to wash.
Peel the screens off with the pull string at either corners at the bottom of insect screen to open/close window. Release the screen when you are done & the insect screen will stick back onto window frame.