Constructed of premium vinyl ester resins, fiberglass dampers and louvers are suited for installation in corrosive environments, including microelectronics fabrication, pulp-and-paper mills, air pollution control systems and corrosion-resistant air exhaust and collection systems. The Swartwout Series includes Models 912 and 914 round isolation/control dampers with an an AMCA leakage Class 1A rating. They offer maximum system pressure ratings of 10” and 30” w.g., respectively, and sizes ranging from 4 to 72” diameter. Models 1104 and 1108 multi-blade control dampers have a pultruded V-groove blade design and maximum system pressure of 20” w.g. Model 1108AF multi-blade control damper has a pultruded airfoil blade design, maximum system pressure rating of 28” w.g. and 316 stainless steel linkage and hardware. Model 426 multi-blade backdraft damper has a pultruded V-groove blade design, a maximum system pressure rating of 10” w.g. and maximum single-section size of 48 x 72”. Model 426AF multi-blade backdraft damper has a pultruded airfoil blade design, a maximum system pressure rating of 16” w.g. and 316 stainless steel linkage and hardware. Also, Model 851FG fiberglass inlet-vane damper is designed to prespin the airflow to match the rotation of the fan wheel, thereby allowing for optimal performance. It is suitable for system pressures up to 10” w.g. and velocities of 6000 ft/min.