Volume Damper Low-Leak OBD 3000-0BDLL-52X30 Specialty Products Spiral pipe diameter must be

Spiral pipe diameter must be 4” larger than Height of the duct opening

stair risers

3/16” crossbars

904 Series Performance Data

Concealed mounting holes

Volume Damper Low-Leak OBD 3000-0BDLL-52X30 Specialty Products Spiral pipe diameter must beh3. 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.