Backdraft Vertical Mount 3550-18X30 Smoke-Fire Damper 904 - Double Deflection Adjustable

904 - Double Deflection Adjustable Aluminum Blade Grille For a 42" x 18" Duct Opening (front blades parallel to shortest dimension)

904 - Double Deflection Adjustable Aluminum Blade Grille For a 36" x 30" Duct Opening (front blades parallel to shortest dimension)

Options * Sleeve variations h3

104 P - four way * Square to round No Labor Collar * 2x2 galvaneal steel panel with seismic support holes * Soft White Options * 104 P D - multi-shutter damper with hinged perforated face * 104 P O - steel opposed blade damper with hinged perforated face * 104 P FR - U

Reinforced welded core and extra supports for heavy duty application

Backdraft Vertical Mount 3550-18X30 Smoke-Fire Damper 904 - Double Deflection Adjustableh3. Standard Features * 3550 Vertical mount * 3560 Horizontal mount air up * 3570 Horizontal mount air down * 3580 Round sizes available 5" to 24" * All non motorized backdraft dampers * Dampers are opened by air pressure differential and closed by gravity * 16 gauge channel frame with 26 gauge galvanized blades * Out of airstream linkage * Blades are vee stiffened 26 gauge for strength and stability * Square steel pivot pins * Nylon bushings * Single