Windows latch: Body: pressure die cast in zinc alloy; powder coted finish Hook & brackets: glass filled nylon Aluminum box louver Blade size available is 4 inch and 5.5 inch This allows users to select between 4 inch glass and 5.5 inch glass sizes Most noted builders and architects use our conceal box louvers for these reasons. Offer high degree of safety from intruders Smooth functioning Toughest heavy duty construction Fine polishing Eagle extrusions Corrosion resistant 4, and 5.5, blade versions available High end office and kitchen ventilations constructions Home constructions Heavy industrial applications Schools and hospitals where safety and continuous usage is required Glass upto 8mm thick is usable Due to their high heat resistance these lovers can be safely powder coated at 300 degree c.Virgin aluminium assures best color anodizing results. Powder coating thicknesses typically range between25 to 200 microns.