A window screen,insect screen or fly screen mesh is a metal wire,fiberglass,or other synthetic fiber mesh,stretched in a frame of wood or metal,designed to cover the opening of an open window.Its primary purpose is to keep leaves,debris,insects,birds,and other animals from entering a building or a screened structure such as a porch,while permitting fresh air-flow.Most houses in Australia,the United States and Canada have screens on all operable windows,which are most useful in areas that have large mosquito populations.Formerly,screen in North America were usually replaced with glass storm windows in the winter,but now the two funchtions are usually combined in combination storm and screen windows,which allow glass and screen panels to slide up and down.

Stainless Seel Window screen: Type 304 is often referred to as "18-8" ( 18% Chromium, 8% Nickel ) with the basic stainless alloy mostly commonly, utilized for wire cloth weaving. It withstands outdoor exposure without rusting and resists oxidation at an elevated temperature up to 1400 Degrees Fahrenheit. Type 304L is very similar to T-304, the difference being the reduced carbon content for better weaving and secondary welding characteristics. Type 316 Stabilized by the addition of 2% molydbenum, T-316 is an "18-8" alloy. It has better resistance to pitting corrosion than the other chromium-nickel stainless steels where brines, sulphur-bearing water or halogen salts, such as chlorides are present. A valuable property of T-316 is high creep strength at elevated temperatures. Other mechanical properties and fabricating characteristics are similar to T-304. Type 316 L is very similar to T-316, the difference being the reduced carbon content for wire cloth weaving and secondary welding characteristics.