Model 1290S is a True Round Smoke Damper ideal for round ductwork applications where building codes require a leakage rated smoke damper for operational smoke control in static or dynamic smoke management systems. Features include a sturdy beaded casing for superior rigidity and a heavy duty 14 ga. (2.0) equivalent laminated blade that is double bolted to axles for positive connection. The 1290S smoke damper is designed and tested to provide premium performance and offers the lowest leakage class available, qualified for installation with airflow in either direction and inverted mounting.