The ELBD812 Automatic Intake Dual Combination Damper Louver has 4" deep louver blades, .050" backdraft damper blades and a 45 degree fixed blade angle. It features:
• 40% Free Area
• All aluminum construction for low maintenance and high resistance to corrosion.
• Operable blades that start to open at .16" w.g. static pressure and are fully open at .23" w.g. static pressure.