The DuraTech 10 Class A Chimney Pipe Firestop Radiation Shield is used in ceiling floor penetrations other than those that include the ceiling support.Fits on underside of ceiling and adjusts to cover framing Use in Ceiling Floor Penetrations when Ceiling Support is not Used UL ListedADA Compliant: No Bottom Diameter: 12-1 8 Collection: DuraTech Fuel Type: Coal, Gas, Oil, Wood Height: 21 Inner Diameter: 10 Length: 18 Material: Galvanized Steel Pipe Class: Class A Pipe Shape: Round Style: Functional Vent Construction: Double Wall Weight: 13 Width: 18