List as duct size (WxH) width x height – all damper will be 1/4″ smaller both ways
Aluminum: .063 3003 Aluminum with alum. hardware and st. stl set screws
Stainless steel: 304 stainless steel with st. stl hardware
Galvanized or stainless steel (both with cast handles)
Above quadrants with 2″ standoff in galvanized, aluminum or stainless steel.
For insulated duct: Damper undersized and insulation stops attached to damper rods for 1″ and 1/2″ insulation. Upon request.