Product details:

452 Square-ft, max velocity 2500 fpm, vertical mounting position, blade material mill finish aluminum, extruded aluinum frame and galvanized tie rods, for use with vertical mounted exhaust fans single- and double-panel exhaust shuttersefficient shutters for direct- or belt-driven exhaust fans are designed to prevent air backflow when the fan is off. Counterbalanced louvers with felted edges except fiberglass models open easily and seal quietly. Units with 54in and 60in galvanized and aluminum shutters have 4 additional tie rods on the discharge side for smooth, quiet operation. Exhaust only mount: vertical max. Velocity: 2500 fpm 1-1/2in flangefront-flange, extruded aluminum framefor cabinet fans and flush-mount wall exhaust applications. Frame has g-90 galvanized steel tie rods and stainless steel rivets and pivot pins. Mill-finish aluminum louvers with galvanized steel reinforcement strip open easily and minimize load on the fan.