High quality extruded aluminum profile with 30 mm flange width as.
Foam gasket toavoid air leakage.
Aluminum sheet as standard and galvanized steel sheet as option.
Blades are sealed with foam gasket at the bottom to avoid rattling noise and to provide air tight operation.
Blades open full or to any angle depending on the air velocity. Blades stay in position of opening without fluctuating when there is constant air flow. Blades close quietly when the air flow stops.
Designed to maintain constant pressure level inside pressurized rooms by relieving excess air when it exceeds the desired limit.