The EM-40 series are horizontally mounted backdraft dampers designed to allow vertical airflow down and prevent reverse airflow up. Model EM-40 has no flange, model EM-41 has a flange on the discharge side, and model EM-42 has a flange on the intake side. All dampers in this series open by air pressure differential and close by gravity. This series includes adjustable counterbalance weights to assist closing.

• Aluminum construction
• Pressure: Up to 10 in. wg
• Velocity: Up to 3500 fpm
• Temperature: Up to 180°F