Standard and high performance counterbalanced backdraft dampers are designed to automatically prevent the backflow of air while allowing for automatic air intake or exhaust/pressure relief in medium duty and heavy duty commercial and light industrial HVAC applications are available. Corrosion-resistant extruded aluminum construction highlights the model’s features, which include a reinforced mitered corner frame that resists racking and aerodynamic blades that overlap the jambs for maximum weather protection. Extruded PVC blade seals provide quiet closure as well as extra weather protection.