Parallel Blade Volume Damper 3000P-18 Specialty Products Standard collar diameter is the

Standard collar diameter is the same as the diffuser size

Interlocking steel roll-formed blades

904 - Double Deflection Adjustable Aluminum Blade Grille For a 20" x 10" Duct Opening (front blades parallel to shortest dimension)

Countersunk mounting holes for flush appearance with color matching Phillips Pozidriv screws

Designed to handle high volumes of air with horizontal flow

Parallel Blade Volume Damper 3000P-18 Specialty Products Standard collar diameter is theh3. Standard Features * 16 gauge galvanized channel frame * Parallel blades are cee 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. Options * 3000 PLL Low Leak Air Control