Volume Damper Low-Leak OBD 3000-0BDLL-72X60 Step Down Ceiling Diffuser For damper free area chart

For damper free area chart A click here * 2663 - Out-of-Airstream fire door

904 - Double Deflection Adjustable Aluminum Blade Grille For a 20" x 14" Duct Opening (front blades parallel to shortest dimension)

Louvers will be Parallel to the First Dimension

2x4 T-Bar (22" x 46" duct)

Uniform 360 degree discharge pattern

Volume Damper Low-Leak OBD 3000-0BDLL-72X60 Step Down Ceiling Diffuser For damper free area charth3. Standard Features * Opposed blade operation for precise volume control * 16 gauge galvanized channel frame * Blades are vee stiffened 16 gauge galvanized for strength and stability * Blades pivot on non metallic celcon bushings * 1 2" square zinc plated steel pivot pins * 1 2" square zinc plated steel adjustable operating shaft extending up to 4" beyond the air control frame * Single blades on dampers with a height of 12" or less * Mill finish h3.